Seed Identification Manual [2nd printing, Reprint 2020 ed.] 9780520318724

Citation preview

Seed Identification Manual

Seed Identification Manual Alexander C Martin and William D. Barkley

University of California Press Berkeley, Los Angeles and London

UNIVERSITY O F CALIFORNIA PRESS, BERKELEY AND LOS ANGELES UNIVERSITY O F CALIFORNIA PRESS, LTD., LONDON, ENGLAND

© 1 9 6 1 BY T H E REGENTS O F T H E UNIVERSITY O F CALIFORNIA SECOND PRINTING, 1 9 7 3 ISBN: 0-520-00814-6 LIBRARY O F CONGRESS CATALOG CARD N U M B E R : 61-7528

Designed by Howard H. Bezanson MANUFACTURED IN T H E UNITED STATES O F AMERICA 3 4 5 6 7 8 9 0

Acknowledgments

The Fish and Wildlife Service of the United States Department of the Interior, particularly as represented by its Branch of Wildlife Research, deserves credit for making this manual possible. It contracted for the extensive series of photographs, made available the outstanding seed collection at its Patuxent Wildlife Research Center, Laurel, Maryland, and aided substantially in other ways. Special acknowledgment is also due Arnold L. Nelson, formerly Director of the Patuxent Wildlife Research Center. His name might well have been included in the authorship because of valuable consultation given during all phases of the work and because his active interest brought essential financial support. Thanks are also given to many individuals who helped with various aspects of the undertaking.

ALEXANDER C .

MARTIN

WILLIAM D .

BARKLEY

Contents

Introduction Seed Photographs

7

Farmlands Weeds, Arranged Systematically (Weeds I), 9 Weeds, Arranged by Physical Features (Weeds II), 47 Crops, 73 Wetlands Aquatics, 77 Marsh Grasses, 83 Marsh Sedges, 87 Other Marsh Plants, 93 Woodlands Woody Plants, 101 Nonwoody Plants, 119 Identification Clues

123

Selected Bibliography

207

Index

211

Introduction

This manual is an attempt to meet the long-standing need for a reference work dealing exclusively with seed identification. The ability to recognize seeds, always important in farming, has become even more essential in modern scientific agriculture: without it, there would be little merit in perfecting methods of growing useful plants. But utility for human consumption, whether as food or in the clothing and construction industries, is not the sole criterion for deciding which plants are useful. Increasingly in recent decades, new knowledge about the interdependence of forms of plant and animal life has been made available, and the public has been alerted to the dangers, both aesthetic and economic, of allowing our natural resources to dwindle. Plants formerly thought to be of little worth have been found to be good, because they provide food and cover for wildlife, or protect watersheds by their quick regrowth over damaged lands. The number of plants regarded as useful and the importance of knowing their seeds have grown accordingly. Of no less importance, however, is the identification of undesirable seeds. On behalf of the crop harvesters and the conservationists, whose ideas of "undesirable" differ somewhat according to their aims, a continual war is being waged against plants that are unwanted for one reason or another. Plantquarantine officers and chemical manufacturers, agricultural experiment stations and seed-testing laboratories work vigilantly in this unceasing fight, in which millions of dollars are expended every year, and millions more are lost through reduced crop potentials. While the value of a wide acquaintance with seeds, both "good" and "bad," has thus been growing at an accelerating rate, the tools for obtaining this knowledge have remained grossly inadequate. The seeds of some genera have apparently not been illustrated or described in published form—or at least, not amply enough to identify them. For other genera, the seed characteristics have

INTRODUCTION

been reported, but in papers that are not easily accessible. For the most part, with a few notable exceptions, the available information about seeds is given only in bits, here and there, in works mainly concerned with other aspects of plant life. To remedy this situation, the authors of this manual have brought together, for direct observation and study on a comparative basis, pictures and practical descriptions of as large and representative a collection of seeds as possible, within the spatial and other limitations mentioned below under Basis for Inclusion. The immediate aim of the manual is to help agriculturists, foresters, wildlife biologists, and others interested in land-use programs to identify the seeds in their particular ecological fields of interest. With this practical aim in view, the authors have, in the main, restricted the content of the descriptions to the characteristics useful for identification. Also, bearing in mind the different backgrounds of the probable readers of this manual in respect to scientific preparation and experience, the authors have thought it best to keep the descriptions nontechnical, so far as was feasible, and thus adapt the material to a broad range of interests and skills.

Definition The term seed must here be understood in its broad, popular sense. It is applied not only to true seeds, but also to equivalent structures which look like and function as seeds. Technical designations for seedlike dry fruits are indicated parenthetically in the text.

Plan of the Book Because the quickest and best way to form a true concept of an object, short of seeing the thing itself, is to examine a good picture of it, the dominant principle governing the order, proportions, and mode of presentation of the contents of this book has been emphasis on illustrations. The manual consists of two major parts, one wholly photographic except for legends and a few explanatory remarks, and the other primarily textual. The pictorial part is given priority by being the larger and by being placed first. The photographs, most of which are magnified, usually show several views of each seed in detail. The superior effectiveness of pictures suggested setting life-sized silhouettes within the plates themselves, so that the reader could receive an image of the seed's real size at once, and need not attempt the difficult feat of translating numerical magnifications into spatial terms. Again in accord with the visual principle, the textual part of the manual is amply illustrated with

2

INTRODUCTION

288 figures in the form of line drawings and diagrams, and the generic descriptions are accompanied by references to the corresponding plates. In the first part of the book, headed Seed Photographs, the photographs are organized systematically within eight plant categories, grouped in three ecological sections with the headings of Farmlands, Wetlands, and Woodlands. The sectional groupings should simplify and expedite identification by enabling the investigator first to classify a seed roughly by its habitat, thus eliminating the need to compare it with seeds from other habitats. The names of these ecological sections and the designations of general types of plants (Weeds, Crops, Aquatics, and so on) must be recognized as merely convenient, short labels that require some qualification or interpretation, since a certain amount of overlapping in their meaning and application is inevitable. The heading Farmlands is intended in a loose sense, to include not only the fields tilled for crops but also rangelands and other open, uncultivated fields. That is why so many wild plants that are not clearly pest species are included under the subheading Weeds. Conversely, under Wetlands are some grasses which flourish in seasonally damp fields and which therefore sometimes interfere with crops. The heading Woodlands also needs a liberal interpretation. Some of the plants included can grow in open places as well as in wooded areas. The word weeds, in its most derogatory sense, is of course a relative term, its application partly dependent on the objectives of the person who uses it. In this manual the subheading Weeds is interpreted in a broad sense, so as to include in the classification, alongside the plants that are objectionably aggressive or even poisonous, not only many harmless wild plants but also a number that are a valuable source of food and cover for many kinds of wildlife, and some that are very useful as soil binders. The plant-family sequence used within the limits of the ecological units of Farmlands, Wetlands, and Woodlands and their plant categories has been supplemented by a physical-feature arrangement in one gallery. This will enable investigators, whether botanists or nonbotanists, to identify seeds by simply matching unknowns with pictures which are segregated on the basis of distinctive shapes and appendages. The plan provides an effective short cut, as compared to scanning all or many of the pictures in a family-order gallery, but the additional space it requires can be justified only by an important, large group. Such a group is that of weed seeds. Because of its special interest to technicians and investigators in several land-management fields, as well as to farmers, plant-quarantine officers, and others, the artificial system of photograph organization has been applied to it. In the subdivision called Weeds, Arranged by Physical Features, winged seeds are grouped together, as are seeds with

3

INTRODUCTION

pappus, others with awns, and still others of special shapes such as spheroid, flattish, or angular. Seeds on the border line between two or more types of shape are often difficult to place satisfactorily, but the preliminary key, figure 1, helps to define the meaning of the designations used and also indicates the series of plates in which each class of related physical features is illustrated. This subdivision, of course, duplicates much of the systematic subdivision on Weeds, though not all of it. Altogether, there are 824 photographic plates, showing the seeds of more than 600 plant species from various parts of the United States. The common plant names used throughout the manual are based in general on those in Standardized Plant Names, by Harlan P. Kelsey and William A. Dayton, prepared for the American Joint Committee on Horticultural Nomenclature (2d ed.; Harrisburg, Pa., J. Horace McFarland Co., 1942), but some stylistic modifications have been made in the longer and more unwieldy compounds. The descriptive section on Identification Clues is the second major part of the book. The seeds presented in the photographic guide are here approached analytically. By means of text and figures this part of the manual points out, as its heading implies, the seed characteristics that are especially valuable for identification. It consists of a single series of descriptions with appropriate illustrations, arranged in systematic order. As explained under Procedure in Seed Identification, below, it was thought best to place the emphasis on the seed traits of families and genera; usually, species are mentioned or illustrated only as examples of the larger groups. Normally, there is a brief treatment of the family traits of the seeds, followed by several seed descriptions for the genera of that family shown in the photographs, two or three genera with very similar seeds occasionally being treated together; and if only one genus of a family is represented the family description is omitted. One marked departure has been made from the rule of describing the seeds genus by genus. The immense and important family of the Gramineae, though represented in the plates by more than forty genera and nearly twice as many species, is discussed chiefly at the family and tribal levels and not in any separate generic descriptions, because the Department of Agriculture's thorough and well-illustrated Manual of Grasses is readily available. Thus it was possible to avoid the numerous and repetitive descriptions without leaving a serious gap. The section on Identification Clues is intended primarily to enable the reader to confirm the preliminary identifications of families and genera which he has made by examining the photographs. In addition, the information on the generic and family traits of seeds will be serviceable in guiding him to the proper

4

INTRODUCTION

systematic starting point; and in this connection the clues on internal morphology should prove especially helpful.

Basis for Inclusion It can be anticipated that some will wonder, regretfully, why the manual was limited to 600 species and why this or that particular seed was not included. The reason for this is essentially the same one that necessitated reproducing the photographs in black and white rather than in color, namely, prohibitive cost. The problem of limiting the number of genera and species to a total that could be treated feasibly in one moderate-sized volume was further complicated by the necessity of keeping the selection representative of botanical groups, geographic areas, and the interests of various scientific and economic fields. A nationwide perspective has been used in choosing genera and species for inclusion in the ecological sections and plant categories. Selection was based, for the most part, on the abundance, widespread distribution, and economic or other importance of the plants or plant groups. Naturally, in some instances the limits for inclusion and exclusion were very difficult to decide. The category Crops was purposely restricted, partly because the public is already well acquainted with most of the more common seeds, and also because there have been many publications on the numerous varieties of cultivated plants.

Procedure in Seed Identification Sometimes one clue, if extreme and unique, serves alone to identify a seed. But more commonly, several different features in combination are required for a positive determination. Frequently a seed can be identified to the species as reliably as can the whole plant from which it was obtained. More often, however, this is not possible, and in many genera the determinations of identity should be left at the genus level to avoid an unjustifiable danger of error. The most useful clues for recognition of seeds are usually the shape, the size, and peculiarities of the surface and coloring. Seed surfaces vary from smooth and glossy to dull or rough; surface irregularities include pittings, grooves, and other types of sculpturing. Characteristics of the attachment scar (hilum), particularly its shape, size, and position, are often significant in narrowing the range of genera or species to be considered. Also, the presence of any noticeable external features such as wings, pappus, spines, awns, or hairs is likely to be helpful in placing the seed correctly. Especially useful clues to the family or genus of an unknown seed are available for those who are willing to delve into its internal characteristics. These

5

INTRODUCTION

include the embryo's shape, size, and position and its relation to endosperm, if the latter is present, and also the wall's thickness, texture, and inner-surface markings. A quick check on a seed's internal morphology can often indicate its family or genus and thus help the investigator avoid serious mistakes about seeds which look surprisingly alike from the outside, but internally are very distinct.

6

Seed Photographs

This pictorial part of the manual, containing 824 plates, is divided into the three habitat classifications of Farmlands, Wetlands, and Woodlands, each of which is again divided into two or more categories on the basis of general types of plants. Within each plant category the seeds are presented in systematic order; but, in addition, about two-thirds of those in the first and largest category, Weeds, are presented a second time, arranged to exemplify the more important traits of their appearance useful for identification. More than six hundred species from the continental United States are shown. The seeds pictured here are described in the second part of the manual, headed Identification Clues, in which the discussion of each genus or group of similar genera is keyed to the corresponding plate or plates by cross reference. Reference from plate to text can be made through the Index. Since nearly all of the seed photographs are magnified, an accurate impression of the size of each seed is conveyed by a small, life-sized photograph in silhouette, set in the lower left corner of the plate; but for the very few seeds too large for the silhouette method (see pis. 553, 555, and 752-755), the inset box is used for indicating size by figures, in the conventional way. Actual measurements are regularly included in the generic descriptions in Identification Clues.

Farmlands Weeds, Arranged Systematically (Weeds I)

Farmlands, as construed here, include western rangelands, fields, fencerows, gardens, roadsides, and open places that harbor weedy or other wild plants. Some of the plants in this section are not weeds in the strict sense. Many of the 307 species illustrated are important both to agriculturists and to wildlife biologists. Representatives of the genera shown here are also included in the following unit on Weeds, Arranged by Physical Features.

FARMLANDS WEEDS I

PLATES 1 - 9

1. Bromus secalinus Chess

2. Bromus catharticus Rescuegrass

3. Bromus tectorum Cheatgrass

4. Festuca octoflora Fescue

5. Festuca obtusa Fescue

6. Tridensflava Purpletop

7. Poa annua Annual Bluegrass

8. Poa pratensis Kentucky Bluegrass

9. Eragrostis cilianensis Stinkgrass

10

FARMLANDS WEEDS I

PLATES 1 0 - 1 8

10. Agropyron repens Quackgrass

11. Hordeum pusillum Little Barley

12. Avena fatua Wild Oats

13. Lolium perenne Ryegrass

14. Lolium temulentum Ryegrass

15. Holcus lanatus Velvetgrass

16. Agrostis alba Redtop

17. Muhlenbergia schreberi Nimblewill

18. Stipa viridula Needlegrass

II

FARMLANDS PLATES 1 9 - 2 6

WEEDS I

19. Sporobolus cryptandrus Dropseed

20. Sporobolus asper Dropseed

21. Aristida virgata Three-awn

22. Eleusine indica Goosegrass

23. Dactyloctenium aegyptium Crowfootgrass

24. Cynodon dactylon Bermudagrass

m k P

y

fft WW i r

.

I

• f i f

/

¿¡k

C m l b - J -v

m *i¥ W

V 25. Bouteloua curtipendula Grama

12

1

26. Bouteloua gracilis Grama

'

m if If

FARMLANDS WEEDS I

27. Digitaria Crabgrass

PLATES 2 7 - 3 3

filiformis

30. Leptoloma cognatum Leptoloma

28. Digitaria ischaemum Crabgrass

29. Digitaria sanguinalis Crabgrass

31. Paspalum ciliatifolium Paspalum

32. Paspalum boscianum Bullgrass

33. Paspalum laeve Paspalum

13

FARMLANDS WEEDS I

PLATES 3 4 - 4 1

34. Panicum capillare Witchgrass

35. Panicum dichotomiflorum Panicum

36. Panicum lindheimeri Panicum

37. Panicum texanum Panicum

38. Setaria viridis Bristlegrass

39. Setaria verticillata Bristlegrass

40. Setaria lutescens Bristlegrass

14

41. Cenchrus pauciflorus Sandbur

FARMLANDS WEEDS I

PLATES 4 2 - 5 0

42. Andropogon virginicus Broomsedge

43. Andropogon scoparius Bluestem

44. Sorghum halepense Johnsongrass

45. Cyperus schweinitzii Flatsedge

46. Commelina crispa Dayflower

47. Commelina virginica Dayflower

48. Tradescantia virginiana Spiderwort

49. Eriogonum fasciculatum Eriogonum

50. Eriogonum alatum Eriogonum

15

FARMLANDS PLATES 5 1 - 5 8

WEEDS I

51. Rumex acetosella Sheep Sorrel

52. Rumex crispus Dock

53. Polygonum aviculare Knotweed

Additional species of Polygonum are illustrated in plates 631-642 and in figures 71-76

54. Polygonum cilinode Knotweed

55. Polygonum convolvulus Cornbind

56. Chenopodium ambrosioides Wormseed

57. Chenopodium album Lambsquarters

16

58. Chenopodium hybridum Goosefoot

FARMLANDS WEEDS I

PLATES 5 9 - 6 7

59. Cycloloma atriplicifolium Ringwing

60. A triplex patula Saltbush

61. A triplex semibaccata Saltbush

62. Corispermum hyssopifolium Tickseed

63. Kochia scoparia Summer-cypress

64. Salsola kali Russianthistle

65. Amaranthus hybridus Pigweed

66. Amaranthus retroflexus Pigweed

67. Amaranthus blitoides Pigweed

17

FARMLANDS WEEDS I

PLATES 6 8 - 7 6

68. Boerhaavia wrightii Spiderling

69. Abronia fragrans Sandverbena

70. Oxybaphus nyctagineus Umbrellawort

71. Phytolacca americana Pokeberry

72. Mollugo verticillata Carpetweed

73. Calandrinia caulescens Redmaids

74. Montiaperfoliata Minerslettuce

75. Portulaca oleracea Purslane

76. Portulaca lanceolata Purslane

FARMLANDS WEEDS I

PLATES 7 7 - 8 4

77. Spergula arvensis Spurry

78. Stellaria media Chickweed

79. Cerastium viscosum Chickweed

, «•*£ >* v'

80. Agrostemma githago Cockle

PLATANUS Sycamore (pi. 711) Unique in being club-shaped, with a tuft of stiff, buffy hairs pointed upward from the base; body 8-9 X 1-1.5 X 1 mm.; light brown, with a persistent style base. Without their hairs, sycamore seeds are remarkably similar to those of buttonbush (pi. 795), but the latter are broader, shorter, and 2-celled inside.

ROSACEAE

i

Fig. 128. Platanus occidentalis X 3

Rose Family

Seeds of this large, diverse family have no consistent identifying features, partly because some of them are achenes, others are pits of drupes, and many others are true seeds borne in follicles or fleshy fruits. Endosperm little or none; most of the interior occupied by large cotyledons, which, in some species, embrace the short embryo stalk. MALUS Apple (pi. 712) PYRUS Pear (pi. 713) Similarities in the compressed-ovate to compressed-elliptic seeds of apples and pears support their classification under a single genus, Pyrus. However, seeds of cultivated apples can be distinguished from those of pears fairly readily by the fact

164

IDENTIFICATION

CLUES

that pear seeds incline to be more attenuate, and their surface lacks the fibrous lengthwise striations of apple seeds. Endosperm is negligible in both, except that it is present in small amounts in some species of Malus (fig. 129). PHOTINIA Toyon (pi. 714) Plano-convex; often with a low ridge running lengthwise on the plane surface; purplish brown or reddish brown, dull, with obscure cellular reticulations; 3-4 X 2-3 X 1.5 mm.

Fig. 129. Malus atrosanguinea X 4.5

t

Fig. 130. Photinia arbutifolia X 5

AMELANCHIER Serviceberry (pi. 717) SORBUS Mountain-ash (pi. 716) ARONIA Chokeberry (pi. 715) Seeds of these three genera are similar in size (3-5 mm. long) and in their shape, which is elliptic-ovoid with a somewhat curved or hooked base. One edge is rounded, and the other often nearly straight or incurved and comparatively thin. Generally, however, Amelanchier is dark and large, Sorbus is usually bright brown and comparatively slender, and Aronia is small and dark, with the surface usually roughened by low lengthwise ridges.

#

Fig. 131 .Amelanchier canadensis X 4

Fig. 132. Sorbus aucuparia X 4.5

I

Fig. 133. Aronia arbutifolia X 6.5

COTONEASTER Firethorn (pi. 718) Seeds (nutlets) woody, rounded-triangular with two flat faces and a rounded back on the common species, C. pyracantha, or planoconvex in larger-seeded species; 2.5-5 mm. long. The plane faces are partly or entirely glossy, as if varnished, whereas the rounded side is partly or entirely rough and dull-surfaced.

Fig. 134. Cotoneaster pyracantha X 7.5

CRATAEGUS Hawthorn (pis. 719,720) Seeds (nutlets) mainly rounded-triangular, with two plane faces and a rounded back on which there usually are coarse ridges and grooves; 5-10 mm. long; commonly there is a small hole or notch at one end of the angular edge; wall thick and hard; frequently the nutlets are sterile.

Fig. 135. Crataegus mollis X 3

I

165

IDENTIFICATION

CLUES

ROSA Rose (pis. 724,725) Seeds (nutlets) rounded-triangular and often oblong, usually with a rounded back and two flattish faces joined into an edge bearing a shallow, narrow groove; yellowish to brown; 3-5 mm. long; wall woody, thick, its inner surface lined by a minutely pitted, glossy layer, in which fibers run crosswise and frequently are loose along a cut or break in the wall.

«

Fig. 136. Rosa bracteata X 5

RUBUS Blackberry, Raspberry (pis. 721-723) Seeds (nutlets) various, but generally compressed, ovate or oval-oblong, with a straight edge and a broader, rounded back; faces and back coarsely reticulate, with a narrow groove on the straight edge and a low ridge on the back; usually 2-3 mm. long.

Fig. 137. Rubus cuneifolius. Diagram (right) X 10

PRUNUS Cherry, Plum (pis. 726-730) Plum stones are generally compressed, oval to elliptic, whereas cherry pits are more globose and vary from compressed-oval to spheroid. Both have a low ridge along one side; a section through this shows a channel in the wall, near the outer edge. The inner surface is minutely cellular-pitted. Cherry pits often show a hole at their attachment end. FRAGARIA Strawberry (pi. 107) POTENTILLA Cinquefoil (pis. 108,109) Seeds of these two genera are similar in size and shape, usually 1-2 mm. long, ovate- or ellipticcompressed, frequently arched, with a rounded back and a straight or concave edge. Most species havefingerprint-likesculpturings on the surface. Strawberry seeds are distinct in being broader, particularly at the large end, owing to the outward projection of their attachment area.

166

Fig. 139. Fragaria chiloensis X 14

t

Fig. 138. Prunus angusti/olia X 2

Fig. 140. Potentilla monspeliensis X 19

IDENTIFICATION

CLUES

GEUM Avens (pi. 110) Seed (achene) body elliptic to oblanceolate; usually 2-3 mm. long; dark brown; hairy; with a long,rigidstyletippedby a hook. Endosperm lacking. AGRIMONIA Agrimony (pi. Ill) Globose seed (achene) about 2 mm. across, concealed in a top-shaped covering (hypanthium), the "equator" of which is armed by numerous hook-tipped bristles. Endosperm none.

LEGUMINOSAE

Bean Family

Many legume seeds are characteristically beanlike, having a compressed-oval shape and a conspicuous, notched attachment area (hilum) near the middle of one edge. Many others, however, are different. Some are rodlike, rectangular, or globose, and in some the attachment scar is obscure. Usually the seed coat is thin, smooth, and tough, and in some species it is mottled, streaked, or spotted. The interiors consist mainly of broad, thick cotyledons, but in some the endosperm is extensive and the cotyledons are relatively small. ACACIA Acacia (pis. 731,732) Rather diverse: compressed and oval to elliptic; black to greenish brown; 4-12 mm. long. All species have the faces marked by an oval or elliptic line more or less concentric with the outline of the seed. Endosperm lacking. PROSOPIS Mesquite, Screwbean (pis. 733,734) Compressed and oval, ovate, or elliptic; 2.5-7 mm. long; brown, rather glossy; with a central ring on each face—a feature shared by several other genera. Cross sections show the yellowish embryo sandwiched between 2 hard, glassy layers of endosperm. SCHRANKIA Sensitivebrier (pi. 116) Seeds similar to those of some Desmanthus species; rhomboidoblong and dark, or compressed-elliptic and brown; faces marked by a raised, oblong, central zone.

f I

Fig. 141. Prosopis pubescens X 5

Fig. 142. Schrankia

DESMANTHUS Bundleflower (pis. 112,113) Diverse in different species; D. illinoensis is flattish-ovate, 3.5 X 2.5 X 1 mm., with an oval to elliptic central zone; D. leptolobus is similar but narrowly elliptic, 5X2X1 mm.; other species are somewhat rhomboid, with a hump on each face and bearing a crescentlike mark. Embryo yellowish, sandwiched between layers of hard, semitransparent endosperm.

uncinata X 3.5 |

Fig. 143. Desmanthus illinoensis X 4.5

167

IDENTIFICATION

CLUES

MIMOSA Mimosa (pi. 735) Compressed and oval to elliptic; brown to gray; about 4 X 2.5 X 1.5 mm., except for M. pigra, which is 6 mm. long. The latter and M. pudica have a central ring on each face, whereas other species are marked by a dark crescent on the humplike central area.

t

Fig. 144. Mimosa bitmcifera X 5

CASSIA Senna (pis. 114,115) Diverse externally and internally (figs. 145-147); medium small to large; compressedoval, flattish-circular, flattish-spatulate, or rhomboid. All species have faces marked by an elliptic to circular zone or ring.

Fig. 145. Cassia tora X 3.5

O t

Fig. 146. Cassia ligustrina X 4.5

Fig. 147. Cassia occidentalis X 4

CHAMAECRISTA Partridgepea (pis. 117,118) Distinctive in theirflattish-rhombicor lozenge shape and rows of circular punctations. The two common Eastern species C. nictitans and fasciculata are black, the former more glossy and smaller than the latter. C. leptadenia of the Southwest is brownish.

Fig. 148. Chamaecrista nictitans

Fig. 149. Chamaecrista fasciculata.

Diagram (right) X 5

CROTALARIA Crotalaria (pis. 119,120) Fairly uniform in shape but diverse in size; 2-8 mm. long; compressed or flattish and asymmetric-reniform, with one end arched over only part way toward the other end; often with a curved beak and a prominent notch; glossy to dull, yellowish, brown, or black.

9t

Fig. 150. Crotalaria spectabilis X 5

168

IDENTIFICATION

CLUES

LUPINUS Lupine (pis. 121-124) Distinct in having its attachment scar (hilum) terminal, and often surrounded by a collar which protrudes outward; generally compressed-ovoid; 2.5-10 mm. long; solid creamy or black in a few species, but more commonly mottled or streaked with dark and light markings; often with a squarish lighter-colored zone at one side of the hilum area; endosperm none. MEDICAGO Burclover, Alfalfa (pis. 125,522) Except for M. lupulina, which is compressed-ovoid, Medicago seeds are compressed-falcate, like a new moon with the ends rounded; from the hilum area, a straight, narrow line runs obliquely on each face; yellow to brown, dull; 2-3 mm. long. Alfalfa (M. sativa) seeds are often truncate near the ends; M. arabica has a distinctive point projecting outward from its hilum area. TRIFOLIUM Clover (pis. 126-130) Either compressed-ovoid to ovoid, with a small, circular hilum flush with the surface, or compressed-ovoid and truncate at one end, with the hilum in a depression; seeds various in size, 1-3 mm. long; yellow, brown, black, or mottled; glossy to dull. LOTUS Deervetch (pis. 131-135) Extremely diverse in shape, from ovoid or spheroid (L. tomentellus), rodlike (L. micranthus, scoparius), or compressed-oval, to rhomboid; generally small but ranging from about 1 mm. to 4 mm. in length; hilum small, circular; usually mottled brown, greenish, or black, on a gray or creamy background; glossy to dull or roughsurfaced. MELI LOTUS Sweetclover (pis. 136,137) Compressed-oval, with a small, circular hilum on an edge near one end. M. alba is somewhat truncate at the broader end, is yellow, and has a distinct line running lengthwise from the hilum; other species are brown or greenish brown; M. officinalis shows the lengthwise line only obscurely.

€1

Fig. 151. Medicago lupulina X 9

m &

Fig. 152. Trifolium repens X 9

% %

Fig. 153. Lotus crassifolius X 6

Fig. 154. Melilotus alba X 9

PSORALEA Scurfpea (pi. 138) Compressed, oval to ovoid; 3-6 mm. long; dark-colored or streaked and mottled (P. macrostachya)', hilum oval, white or light-colored, generally with a low ridge or hump near one end; hilum not quite median on seed edge; endosperm none.

169

IDENTIFICATION

CLUES

AMORPHA Leadplant (pi. 736) Compressed, and oval or elliptic to lanceolate; 2-5 mm. long; circular hilum near the end of the nearly straight edge, along which a narrow dark line runs lengthwise; end of seed somewhat arched near hilum; brown, glossy or dull. INDIGOFERA Indigo (pi. 139) Varying from oblong block-shaped or truncate-cylindric (like sawed-off segments of a solid cylinder) to ovoid or spheroid; about 2 mm. long; hilum circular, nearly central on one margin; olivegreen, brown, black, or mottled; I. caroliniana is distinct in its black-eyed hilum.

1

Fig. 15 S.Amorpha canescens X 6

Fig. 156. Indigofera caroliniana X 7.5

TEPHROSIA Hoarypea (pi. 140) Mainly compressed and oval to oblong, often truncate at one end; 2-6 mm. long; hilum marginal, not quite central, with a white, papery collar; in several species, black mottling contrasts with grayish or brownish background. Fig. 157. Tephrosia

ROBIN IA Black Locust (pi. 737) nrgmmna x 6 Compressed, and elliptic or oval, somewhat falcate; fairly large hilum in a notch beside a prominent hump; white collar around the hilum; mottled black on gray or on brown; about 5X3X1.5 mm. SESBANIA Coffeeweed (pi. 143) Oblong-ellipsoid and slightly compressed; 4 X 2.5 X 2 mm.; blackish mottling on gray or brown; hilum circular, nearly central.

Fig. 15S. Robinia pseudoacacia. Diagram (right) X 4

170

Fig. 159. Sesbania macrocarpa. Diagram (right) X 4.5

IDENTIFICATION

CLUES

ASTRAGALUS Loco (pis. 141,142) Diverse: flattish, and oval, ovate, circular, or truncate; usually with the minute hilum in a deep marginal notch; mainly 2-3 mm. long; brown to black or mottled.

Fig. 160. Astragalus brazoensis X 7.5

AESCHYNOMENE Jointvetch (pi. 144) Seeds (borne in rectangular loment segments) flattish-compressed, oval, with a broad, deep hilum notch and a large, oval hilum, which is cleft lengthwise and generally is adjoined by a hump; 4 X 3 X 1.5 mm.; dark brown. Fig.

161. Aeschynomene virginica X 5

DESMODIUM Tickclover (pis. 145-147) Seeds (borne in oval or oval-triangular loment segments coated with hooked hairs) flattish to compressed and oval or ovate to elliptic or somewhat triangular (D. nudiflorum); 2-8 mm. long; brown; hilum small, circular, nearly central, on an almost straight edge; one end of seed usually broader than the other.

Fig. 162. Desmodium dillenii

Fig. 163. Desmodium tortuosum X 7.5

LESPEDEZA Lespedeza (pis. 148-152) Seeds (borne in a pointed pod partially enclosed by the calyx) similar in shape to Desmodium, but proportionately thicker, not as straight on the hilum edge, and the circular, white-lined hilum definitely not central; usually small, 1.5-4 mm. long; green, brown, or black, or mottled. Seeds of native species are generally green or nearly black. The two important annual species can be distinguished readily as follows: Lespedeza striata (Common Lespedeza) Pod acuminate at top. Calyx large, brownish, covering much of pod. Seed mottled, purplish brown. Hilum in a slight notch, on edge near end.

Lespedeza stipidacea (Korean Lespedeza) Pod broad-obtuse at top. Calyx small, semitransparent, covering only basal one-fourth of pod. Seed solid black or purple. Hilum not in notch, and practically on end.

171

IDENTIFICATION

CLUES

Fig. 164. Lespedeza frutescens

VICIA Vetch (pis. 153,154) LATHYRUS Peavine (pis. 155,156) These two genera cannot be distinguished satisfactorily by their seeds; perhaps they should be united. Their seeds are mainly globose or compressed-globose, 1.5-7 mm. across (V. faba is 15 mm. long), cream, brown, or black, with an oval, oblong, or linear hilum. Endosperm none. API OS Groundnut (pi. 814) Rounded rectangular-solid, with irregular or wrinkled surface; 6 X 5 X 4.5 mm.; dark brown; hilum inconspicuous, often with a small, brown, papery attachment at its edge. Endosperm none. GLYCINE (SOJA) Soybean (pi. 523) VIGNA Cowpea (pi. 524) Seeds of both of these genera vary from compressed-oval to spheroid; white or brown to black; and average about 8 mm. in length. They can be distinguished from each other readily by the hilum, which in Glycine is oblong, flush with the surface, and marked by a central lengthwise line or cleft (much as in Vicia and Lathyrus), whereas in Vigna the hilum is generally oblong-wedge-shaped and is covered with hornyappearing material which protrudes slightly above the seed surface. There is a cavity between the cotyledons in Vigna but not in Glycine. Endosperm none. CENTROSEMA Butterflypea (pi. 157) Mainly oblong-solid, with rounded margins and only slightly compressed; 3-4 X 2.5 X 2 mm.; with a large (nearly one-third of the seed length) oval-elliptic hilum surrounded by a dark marginal band, the outer edge of which is rather irregular, in contrast with the regular outer edge of the band on Galactia; reddish brown, with black, irregular or oblong streaks and mottlings; no endosperm.

172

IDENTIFICATION

CLUES

AMPHICARPA Hogpeanut (pi. 815) Broadly compressed-oval, with one straightish side; 3.5 X 3 X 1.5 mm.; hilum oblong, about 1.5 mm. long, whitish, and with a persistent papery collar; dark reddish brown with black streaks and mottlings; no endosperm.

Fig. 167. Amphicarpa

GALACTIA Milkpea (pi. 162) bmcteata Slightly compressed, oblique-ovoid or oblique-truncate; in the common species 2-3.5 mm. long, but in some species, longer; hilum conspicuous, with a broad, dark collar which (in contrast to the collar in Centrosema) is clearly and regularly outlined on its outer margin as well as on its inner one; usually marked by lengthwise dark, mottled bands alternating with lighter ones, or streaked in other ways. No endosperm. STROPHOSTYLES Wildbean (pis. 159-161) Oblong-solid, more or less compressed; 3-8 mm. long; outer coating grayish scurfy, and black underneath (S. helvola, umbellata), or surface smooth and mottled, either brownish or grayish; hilum oblong, covered by white material and bordered by a narrow, black collar. Cavity between cotyledons, as in Vigna; no endosperm.

Fig. 168. Galactia volubilis

Fig. 169. Strophostyles helvola

RHYNCHOSIA Rhynchosia (pi. 158) Compressed or flattish, circular to elliptic, with one edge straight or concave; hilum oval, covered by papery material; reddish brown or grayish and mottled. No endosperm. PHASEOLUS Bean (pis. 163, .525) Diverse in shape, size, and color; compressed-oval, -elliptic, or -lunate, to globose; 4-20 mm. long; white, black, brown, reddish brown, green, or mottled; hilum elliptic to linear, covered with whitish material. No endosperm.

173

IDENTIFICATION

LINACEAE

CLUES

Flax Family

LINUM Flax (pis. 164, 526) Seeds borne in flattish, thin-walled compartments like narrow sectors of a sphere; flat or flattish, elliptic or elliptic-ovate, one side generally nearly straight. Native species 1-2 mm. long; lightcolored. Cultivated flax, L. usitatissimum. 4 mm. long; brown, glossy.

OXALIDACEAE

Oxalis Family

OXALIS Oxalis (pi. 165) Flat, oval-ovate; sculptured with cross ridges, except in O. acetosella, which has longitudinal ridges; reddish brown; generally slightly more than 1 mm. long, but O. acetosella is about 3 mm. long.

GERANI ACE AE

Fig. 170. Linum berlandieri X 5

Fig. 171. Oxalis strida X 14

Geranium Family

Seeds mainly small; ellipsoid to rodlike; embryo folded; endosperm negligible. GERANIUM Geranium (pis. 166,167) Ellipsoid or angular-ellipsoid; often sculptured with a meshwork of cellular reticulations; narrow line from middle of one end extends just over edge; one side often somewhat ridged, with adjoining faces flattish or concave; when outer reticulated coating is removed, an inner glossy brown coat is seen; embryo greenish or yellow, folded; endosperm none or negligible.15

Fig. 172. Geranium carolinianum

ERODIUM Filaree (pis. 168,169) Oblanceolate-cylindric; 3-5 mm. long; a fine line extends from narrowed end up the side nearly 1 mm.; removal of the dull, brownish outer wall reveals an inner glossy brown one; embryo folded; endosperm negligible.16 Fig. 173. Erodium

cicutarium

15 See A Seed Key to Fourteen Species of Geraniaceae, by Margaret R. Murley, Proc. Iowa Acad. Sci. 51:241-246, 1944. 18 See Alfileria (Filaree) Seed, by William A. Dayton, Rhodora, 39:323-325, 1937.

174

IDENTIFICATION

ZYGOPHYLLACEAE

CLUES

Caltrop Family

No consistent family characters in seeds, either externally or internally. TRIBULUS Puncturevine (pi. 170) Seed (hard, dry fruit) distinctive in its 2 tough spines, about 5 mm. long, arising obliquely from a reticulate-ridged, irregular base. Endosperm none. LARREA Creosote (pi. 738) Crescent-shaped, compressed, with the incurved margin narrow; surface rough; brown to black; about 3.5 mm. long.

Fig. 174. Larrea tridentata X 4.5

KALLSTROEMIA Caltrop (pi. 171) Seeds (carpels) woody; flat and broadly wedge-shaped; the flat, glossy, reticulatesculptured faces sloping into a thin, straight edge; the other (rounded) edge is thicker and bears a series of blunt, hornlike tubercles, the bases of which are covered with short, whitish hairs; 4X3X2 mm.; endosperm none.

POLYGALACEAE

Milkwort Family

POLYGALA Milkwort (pis. 172,173) Generally pubescent, and with a papery, whitish aril. Two main types of seeds: one small (0.5-1.5 mm. long), ovoid, and only moderately hairy; the other larger (4-5 mm. long), truncate-oblanceolate, flattish, and densely coated with pubescence.

EUPHORBIACEAE

f •

Fig. 175. Polygala sanguinea X 15

Fig. 176. Polygala grandiflora X 7

Spurge Family

Important diagnostic features of this family are the curved or slanting, fine striations in the seed wall as seen in broken or cut sections; a straight line (often slightly grooved) extending from end to the other; and the usual presence of a terminal knobby outgrowth, the caruncle. Seed shapes are various: compressedovoid to compressed-ellipsoid, or spheroid, quadrangular, or flattish, like thin slices of cake. Cotyledons spatulate, thin, often with a cavity between them.

175

IDENTIFICATION

CROTON Doveweed (pis. 174-178) Usually compressed, and ovoid to ellipsoid or oblong, but some species spheroid; 3-5 mm. long; generally the flattish side consists of two gently sloping faces, the junction of which is marked by a straight, narrow line extending from one end to the other; the end bearing the caruncle is slopingtruncate on one side; surface shallowly reticulatepitted or smooth; commonly mottled with grayish, black, or brown.

CLUES

© ij^Croton punctatus x 3

Fjg

EREMOCARPUS Turkeymullein (pi. 179) This is, in effect, a large (4-6 X 3.5 X 2.5 mm.) Croton, and was formerly classes as such. Its plane faces are pitched at a steeper angle than in Croton, and it has distinctive, large splotches of black on a brownish or grayish background.

ACALYPHA Copperleaf (pis. 180-182) Ovoid;finelyreticulate; smooth, or warty-rough (A. ostryaefolia); small, 1-2 mm. long; brown, gray, blackish, with or without mottlings; longitudinal line evident.

®

Fig. 178. Croton capitalus X 4.5

I

Fig. 179. Eremocarpus setigerus X 4.5

t

Fig. 180. Acalypha virginica X 12

TRAGIA Noseburn (pi. 183) Globose; 4-5 mm. across; mottled brown or grayish; raphe line short (2 mm. or less).

($>

Fig. 181. Tragia urens X 4.5

STILLINGIA Queensdelight (pis. 184,653) Subglobose-ovoid, generally with a sloping face near the caruncle, and with the opposite end broadly truncate; surface warty-rough to smooth; usually silvery gray; 5-7 mm. long.

f)

Fig. 182. Stillingia aquatica X 4.5

176

IDENTIFICATION

CLUES

EUPHORBIA Spurge (pis. 185-190) Rather diverse, but mainly ovoid, quadrangular-ovoid, or ovate plano-convex, with a distinct longitudinal line; smooth or warty-rough; white, cream, brown, or black; 2-5 mm. long, except in the subgenus Chamaesyce, which is distinct in having seeds 1 mm. or less long, and quadrangular (ovoid-quadrangular, oblong-quadrangular, or ovoidtriangular), commonly with a few, low cross ridges.17 Embryo variations are indicated in figures 183-185.

(D fl>

Fig. 183. Euphorbia lathyrus X 3

Fig. 184. Euphorbia vermicidata X 15

EMPETRACEAE

Fig. 185. Euphorbia dentala X 7

Crowberry Family

EMPETRUM Crowberry (pi. 739) Flattish and rounded-triangular, like thin sectors of a sphere; narrow edge nearly straight, except for a low, umbilicus-like protrusion; woody, finely rough-surfaced; brown; 2 X 1.2 X 0.5 mm.

ANACARDIACEAE

Cashew Family

Fig. 186. Empetrum nigrum X 10

Seeds woody or bony; compressed to flattish and oval, ovate, or elliptic, or ovoid to globular; endosperm plentiful to scant. RHUS Sumac (pis. 741-744) Elliptic-ovoid, or somewhat compressed to flattish, and oval or nearly circular; 2-7 mm. long; wall with 2 striate layers and a thin layer between; smooth; brown or gray.

Fig. 187. Rhus glabra X 6.5

Fig. 188. Rhus copallina

17 See the study Euphorbia, Subgenus Chamaesyce, in Canada and the United States Exclusive of Southern Florida, by Louis Cutter Wheeler, Rhodora 43:97-154, 168-205, 223-286, 1941.

177

IDENTIFICATION

CLUES

TOXICODENDRON Poison-ivy (pi. 740) Compressed, ovate to oblong; with lengthwise irregular ridges and grooves; wall with 1 thick, striate layer; about 4 mm. long; light brown. Fig. 189. Toxicodendron diversiloba X 5.5

AQUIFOLIACEAE

Holly Family

ILEX Holly (pis. 745-749) Holly seeds (nutlets) vary in shape from flat and ovate or elliptic to rounded-triangular (like sectors of a sphere), and range in length from 3 to 6 mm.; irregularly ridged lengthwise, or smooth; wall woody; with fibers running crosswise, as evident on surface of smooth species or on edges of cut or broken rough-surfaced ones.

CELASTRACEAE

Fig. 190. Ilex verticillata X 5.5

Bittersweet Family

Seeds enclosed partly or entirely in an aril; generally ovoid to ellipsoid; cotyledons spatulate, thin, in fleshy endosperm. CELASTRUS Bittersweet (pi. 750) EUONYMUS Wahoo (pi. 751) Seeds of these two genera are similar in size (generally 3-5 mm. long), shape (ovoid to ellipsoid), and color (reddish brown). The surface is marked by a lengthwise line, ridge, or groove. Common bittersweet, C. scandens, is distinct in being larger (5-6 mm. long), more regularly ellipsoid, and slightly arched, though one side is nearly straight.

ACERACEAE

I

Fig. 191. Celastrus scandens X 2.5

Fig. 192. Euonymus atropurpureus X 2

Maple Family

ACER Maple (pis. 752-755) The winged seeds (samaras) of different species can generally be distinguished by breadth and length of the wings, by shape and size of the body, and by the angle of at-

178

IDENTIFICATION

CLUES

tachment of the paired seeds.18 Embryo bent or folded, sometimes greenish; endosperm none.

Fig. 193. Acer rubrum

BALSAMINACEAE

Balsam Family

IMPATIENS Jewel weed (pi. 816) Quadrangular-ellipsoid, narrowed toward base, with length-wise ridges; surface commonly warty or wrinkled irregularly; purplish brown or reddish brown; about 4 X 2.5 X 2 mm.; embryo greenish, bluish, or yellow. The two common species cannot be distinguished readily by their seeds.

Fig. 194. Impatiens biflora

RHAMNACEAE

Buckthorn Family

Seeds (some of them nutlets) diverse in size and shape; many broadly roundedtriangular, plano-convex, or globose; wall hard, bony or woody; cotyledons spatulate; endosperm generally present. RHAMNUS Buckthorn (pis. 756,757) Shape varies considerably (figs. 195-197, cross sections), mainly rounded-triangular (R. cathartica acutely rounded-triangular) or plano-convex, usually with a bony attachment base suggestive of a tick head; certain species such as R. crocea and ilicifolia have 18

For these and other characteristics, see Woody-Plant Seed Manual, U. S. Dept. Agr. Misc. Publ. 654,1948.

179

IDENTIFICATION

CLUES

a wedge-shaped opening or groove on one face; plano-convex forms have a distinct lengthwise line on the flat face; 5-10 mm. long; black, brownish, or olive, dull.

«

Fig. 195. Rhamnus alnifolia X 4.5

Fig. 196. Rhamnus cathartica X 3.5

Fig. 197. Rhamnus purshiana X 3.5

CEANOTHUS Buckbrush, Jerseytea (pis. 760,761) Ovoid rounded-triangular, with a broadly rounded back and two nearly plane faces joined in a low, obscure ridge; both ends broadly rounded; 2-4 mm. long; black, brown, or olive, dull or glossy. Fig. 198. Ceanothus cuneatus X 5

CONDALIA Condalia (pi. 759) Circular plano-convex; 2-4 mm. across; brown, dull; borne in pairs in 2-celled, woody, broad compressed-ovoid nutlets. Fig. 199. Condalia obovata X 4.5

BERCHEMIA Supplejack (pi. 758) Oblong-cylindric, slightly compressed, with one end open and a shallow groove extending over both sides, because of the 2 cells inside; woody; light brown; 4 X 3 X 2 mm. Fig. 200. Berchemia scandensX 4

VITACEAE

Grape Family

Seeds woody; wall folded inward in deep grooves, strongly striate in section; generally ovoid rounded-triangular, but some are plano-convex or subglobose; embryo small, basal, in firm-fleshy endosperm.

180

IDENTIFICATION

CLUES

VITIS Grape (pis. 762-764) Ovoid rounded-triangular (sometime elongate), plano-convex (V. rotundifolia), or simply ovoid; marked on the roundish face by a central oval area connected by a groove over the broad end of the seed, and on the plane faces by broad, shallow grooves, on both sides of the central ridge; brown to black; 4-7 mm. long. Fig. 201. Vitis aestivalis X 4

AMPELOPSIS Peppervine (pi. 765) PARTHENOCISSUS Woodbine (pi. 766) Both are similar to Vitis, but proportionately broader and shorter. Woodbine seeds are distinct in the flatness of their plane faces, in the sharply defined margins, and in the comparative thinness of the walls. Ampélopsis is more rounded (subglobose in A. cordata) and heavy-walled.

Fig. 202. Ampélopsis cordata X 3.5

MALVACEAE

Fig. 203. Parthenocissus quinquefolia X 4

Mallow Family

Seeds compressed-reniform to flat or globose; often with external contours showing that the embryo is bent or arched; cotyledons large, thin, and folded, endosperm usually present. SPHAERALCEA Globemallow (pi. 191) SIDALCEA Checkermallow (pi. 192) MALVASTRUM Falsemallow (pi. 193) These closely related genera are difficult to distinguish by their seeds because of overlapping characteristics. All have a deep, broad notch in the attachment area and are compressed-reniform, with one end narrowed; many are coated with hairs or minute protuberances. Sidalcea is distinct in being considerably thicker along its arched back, sloping down to a comparatively thin inner margin, whereas Sphaeralcea and Malvastrum are more uniformly compressed or flattish. Sphaeralcea generally is obliquely reniform and has a coating of hairs, whereas Sidalcea is smooth and Malvastrum generally so.

181

« a o c o IDENTIFICATION

Fig. 204. Sphaeralcea angusti/olia X 12

CLUES

Fig. 205. Sìdalcea neomexicana X 7.5

Fig. 206. Malvastrum exile X 15

SIDA Sida (pi. 194) Rounded-triangular, with two flat faces and a rounded back, like sectors of a sphere, the inner edge narrow and the outer edge of variable breadth in different species; the truncate top with a conspicuous notch beside a pommel-like knob; about 2 mm. long; dark brown to black.

W #1 ft

Fig. 207. Sida rhombifolia X 9

HIBISCUS Hibiscus, Rosemallow (pis. 654,655) Subglobose or ovoid, to compressed or flattish, reniform, generally with a conspicuous attachment scar beside a saddle-pommel knob; surface in most species marked by minute, scurfy protuberances, in rows, or coated with hairs (77. militaris, syriacus, coulteri, denudatus), or smooth (77. esculentus, furcellatus); 2-5 mm. long; brown, olive-green to black.

STERCULIACEAE

Chocolate Family

MELOCHIA Chocolateweed Rounded-triangular, pointed near one end and rounded at the other (no notch); top capped by brownish, papery material, the removal of which shows a circular area marked by fine striations radiating from the center; dark gray or dark brown, splotched crosswise with small, dark markings; 3X1.5X1.5 mm.

HYPERICACEAE

Fig. 208. Hibiscus incanus X 7.5

Fig. 209. Melochia corchorifolia X 7.5

St. Johnswort Family

Seeds minute (0.5-2 mm. long); rodlike to oblong-cylindric or ellipsoid, like some insect droppings; finely to coarsely cellular-reticulate and marked by a lengthwise line and by a nipple-like point at one end.

182

IDENTIFICATION

CLUES

HYPERICUM St. Johnswort (pi. 817) ASCYRUM St. Andrewscross (pi. 818) These two genera are similar in the family characteristics noted above. Ascyrnm seeds, however, are slightly thicker, average 0.75-1 mm. long, and are uniformly dark (black or dark brown). Hypericum seeds vary more in length and color: some slender, slightly arched, black ones (H. nudiflorum, prolificum, etc.) are about 2 mm. long; a few cream-colored ones are less than 1 mm. long (H. gentianoides, punctatwn); and still others are brown and intermediate in length (H. canadense, denticulatum, virginicum, etc.).

VIOLACEAE

Violet Family

f

VIOLA Violet (pis. 195-197) Ovoid, with a lengthwise line on one side and scurfy material (the caruncle) at the attachment end; cream, brown, dark olive, mottled, or black; generally about 2 mm. (1.5-3 mm.) long.

Fig. 210. Viola eriocarpa X 7.5

PASSIFLORACEAE

Passionflower Family

PASSIFLORA Passionflower (pis. 198,199) Flattish, ovate to elliptic; coarsely marked by shallow pittings, or by crosswise ridges and narrow lengthwise lines (like longitude and latitude lines); 4-6 mm. long; wall thick, woody, striate; cream to black.

f

Fig. 211. Passiflora incarnata X 3

LOASACEAE

Loasa Family

MENTZELIA Prairiestar (pis. 200,201) Diverse in shape and size; flat, thin, and with an encircling wing (M. decapetala, laevicaulis, multiflora, stricta, and wrightii), or 3-sided and truncate, with grooves in each angle (M. dispersa, micrantha), or irregularly angled (M. lindleyi), or flattish-oblong, with a low ridge on one side (M. oligosperma). Whether the seed is winged or not, the surface usually has minute, papillae-like protuberances, which give it a characteristic beady, reptile-skin appearance. Length varies from 1 to 4 mm.; and color from cream to dark, spotted with gray.

183

IDENTIFICATION

«

f

Fig. 212. Mentzelia decapetala X 5.5

CACTACEAE

CLUES

Fig. 213. Mentzelia lindleyi X 9

Cactus Family

Seeds of this family are similar internally in being bent, with little or no endosperm; externally, they are of two main types: (1) comparatively large, flattish, light-colored (Opuntia); or (2) smaller and generally dark (other genera). OPUNTIA Pricklypear (pis. 202,203) Flattish-subcircular, either with a distinct groove parallel to the margin (as in O. compressa. engelmannii, erinacea, humifusa, macrocentra, polycantha, pollardi), or without a bordering groove (as in O. imbricata, leptocaulis, parishii, spinosa). Cream tr> mm across.. across to licrht llgnt hrownDrown, XV 60 mm.

9@

F l g 214

'

untia ' °PX 5.5

leptocaulis

Fi

8-pollardi 215. Opuntia X 4.5

CERE US Giantcactus (pi. 204) Compressed-ovoid, with a truncate, hollow base; black, glossy, and obscurely cellular-reticulate (C. giganteus, pentagoneus), or dull and rough or pitted (C. greggii); 2-4 mm. long; endosperm none.

MAMMILLARI A Cactus (pi. 205) Diverse in shape and surface characteristics: ovoid (M. missouriensis) to compressed-ovoid (M. micromeris, vivipara), or flattish-reniform (M. robustispina). M. missouriensis is black and rugosepitted and about 1.5 mm. long; M. micromeris is black and nearly smooth, about 2 mm. long, and has a large cavity; M. robustispina is brown, smooth, cellular-reticulate, and 4 mm. long; M. vivipara is also brown, but is cellular-pitted, and 2 mm. long.

Fig.

a

2\^~Mammillaria x5

robustispina

Fig.

f

m

217. Mammillaria vivipara X 10

184

IDENTIFICATION

CLUES

ECHINOCACTUS Cactus (pi. 206) Ovoid to compressed-oval or somewhat reniform; all with a cavity at or near the base and usually black; most species with surface finely or coarsely roughened by protuberances or pittings, but a few glossy (E. texensis, xeranthemoides); 1-4 mm. long.

r

Fig. 218. Echinocactus intertextus X 7.5

#

r

Fig. 219. Echinocactus polycephalus X 5

ELAEAGNACEAE

t

Fig. 220. Echinocactus setispinus X 14

Elaeagnus Family

Seed enclosed in a hard, persistent covering (partly calyx) in Elaeagnus; in Shepherdia, borne in a berry-like fruit from which it escapes readily. ELAEAGNUS Russianolive (pi. 767) Ellipsoid, pointed-ellipsoid, or spindle-shaped, with dark and light lengthwise ribs alternating on the hard, fibrous wall; light stripes commonly silvery whitish; 6-10 mm. long. Endosperm none. SHEPHERDIA Buffaioberry (pi. 768) Compressed-oval, some plano-convex; a notch on one side of base and a lengthwise groove from notch upward on both faces; glossy, black or dark brown; 4-5 mm. long.

LYTHRACEAE

t

Fig. 221. Shepherdia argentea X 5.5

Loosestrife Family

DECODON Waterwillow (pi. 656) Prismatic-wedge-shaped or pyramidal, with 2,3, or more plane faces, narrowed downward from a broad, slightly rounded top to a pointed base; varnished brown with darker lines; 1.5X1X1 mm. Endosperm none.

ONAGRACEAE

Evening-primrose Family

Seeds minute, small, or medium; shapes various, often elliptic; endosperm none.

185

IDENTIFICATION

CLUES

JUSSIAEA Waterprimrose (pis. 657,658) In certain species {J. leptocarpa, pilosa, suffruticosa) the seeds are partially enclosed in a heart-shaped block of corky material, and in J. diffusa they are buried in oblongtruncate, oblique chunks of corky wood. The true seeds are minute, less than 1 mm. long; ellipsoid or arched-ellipsoid, with narrowed or obtuse ends; one side is somewhat compressed and has a thin, dark, lengthwise flange; cream to brown. OENOTHERA Evening-primrose (pis. 207-209) Diverse; variously angled, often with a rounded side, or angular-ellipsoid, spindleshaped to flattish-oblong, or angular-lanceolate; smooth- to rough-surfaced, thin- to thick-walled; yellow-brown to dark purplish brown; 1-4 mm. long. GAURA Gaura (pi. 210) Seeds (nutlike fruits) woody; generally 4-sided, spindle-shaped, except in G. parviflora, which is elongate-ellipsoid with irregular rounded ridges and grooves; in most species, the seeds are hairy and have a lengthwise rib median between the angles and extending halfway up from the base; about 6 mm. long.

TRAPACEAE

Waterchestnut Family

TRAPA Waterchestnut, Watercaltrop (pi. 555) The hard, large (3-4 cm. across), nutlike seeds (mericarps) are somewhat top-shaped and are armed on their thick median zone with 4 stout, retrorsely barbed spines, which are attached to bulbous bases and make the seed somewhat 4-angled; dark to black. Endosperm none.

HALORAGIDACEAE

Watermilfoil Family

Seeds (nutlets) woody, oblong or oblong rounded-triangular to ellipsoid, or triangular; embryo linear in endosperm of variable amounts. HIPPURIS Marestail (pi. 556) Oblong-cylindric, with short points on both of the obtuse ends; an obscure line extends from top to bottom, on both sides of seed; wall thick, soft-woody; embryo circular in cross section; 2 X 1 X 1 mm.

186

Fig. 222. Hippuris vulgaris X 10

IDENTIFICATION

CLUES

MYRIOPHYLLUM Watermilfoil (pis. 557, 558) Oblong rounded-triangular, 1.5-2 mm. long, except in M. tenellum, which is oblong-cylindric and barely 1 mm. long. M. scabratum has its outer (rounded) margins fringed with toothlike processes; M. spicatum is obscurely warty on its back (rounded) surface. Worn seeds generally are open at one end. Fig. 223.

Myriophyllum spicatum X 11

PROSERPINACA Mermaidweed (pi. 559) Broadly triangular (ovoid-pyramidal), with thin margins in P. palustris and rounded margins in P. pectinata; reddish brown; 4 X 3 X 3 mm.; interior distinctive in showing 3 cylindric cells, one in each of the angles.

ARALIACEAE

Fig. 224. Proserpinaca pedinata X 7.5

Aralia Family

ARALIA Aralia (pis. 770,771) Flattish-oblong, pointed near base; two distinct groups of species: (1) seeds small (about 2 mm. long), whitish with a satin sheen, wall rather thin and with crosswise surfacefibers(A. californica, cordata, racemosa); (2) seeds larger (2.5-4 mm. long), thick-walled, roughsurfaced, brown (A. hispida, nudicaulis, spinosa).

U M BELLI FE RAE

f

C 3

Fig. 225. Aralia hispida X 7

Parsley Family

Seeds (mericarps) usually flattish, plano-convex, or concave-convex; outlines various: circular, oval, or elliptic, to narrow and elongate. Surface has several lengthwise ribs or ridges; embryo small, basal in fleshy firm endosperm. CENTELLA Centella (pi. 659) HYDROCOTYLE Pennywort (pi. 660) Flat, with inner edge straight, outer edge rounded; often a pair of seeds remaining united by their inner edges and appearing kidney-shaped. Centella is distinct in having 2 or 3 branched, prominent, curved, veinlike ribs, whereas Hydrocotyle has, if any, 1 or 2 straight, less prominent, and unbranchedribs.Centella seeds are 4 X 3 X 0.5 mm.; Hydrocotyle seeds are slightly smaller.

Fig. 226. Centella asiatica X 7.5 Fig. 227. Hydrocotyle umbellata X 12

187

IDENTIFICATION

CLUES

DAUCUS Wildcarrot, Queen-Annes-lace (pi. 211) Elliptic plano-convex, with the margins and 3 ridges on the back bearing long, narrow, whitish, flat, spinelike processes hooked at the end and with bristly hairs in rows between the crowned ridges; 3-4 mm. long. Fig. 228. Daucus carota X 7.5

CORNACEAE

Dogwood Family

Seeds (pits of drupes) hard, bony-woody; globose, ellipsoid, or compressedoval to compressed elliptic; embryo spatulate in fleshy endosperm. CORN US Dogwood (pis. 772-775) Seed generally globose to ellipsoid; containing 2 seed chambers, or often only one; lengthwise groove or line all the way around, from top to bottom. The ellipsoid forms (C. canadensis, florida, nuttallii, sessilis) have no ridges, except for low obscure ones in C. sessilis, whereas ridges are usually evident on the globose forms.

Fig. 229. Cornus canadensis X 7

Fig. 230. Cornus amomum X 3.5

Fig. 231. Comus florida. Diagram (right) X 2.5

NYSSA Blackgum (pi. 769) The two widespread species, N. biflora and sylvatica, are similar in being compressed-ovoid or compressed-ellipsoid, and in having several grooves or stripes on each face; about 7 X 5 X 3 mm.; TV. aquatica and ogeche are much larger (about 2 cm. long) and are rough, with deep grooves.

ERICACEAE

I

Fig. 232. Nyssa biflora X 2

Heath Family

Seeds (some of them nutlets of drupes) diverse; minute and delicate; or medium small and compressed, oval to elliptic; with a hard, glossy, often reticulate surface; or irregular, bony nutlets. Embryo linear to spatulate in fleshy endosperm.

188

IDENTIFICATION

CLUES

GAULTHERIA Wintergreen (pl. 776) Flattish, irregularly angled and curved, often ovate or wedgeshaped, with a broad, rounded top; glossy brown; about 1 mm. across; the cellular reticulations are obscure on G. procumbens and distinct on G. shallon (which is less glossy). Fig. 233. Gaultheria shallon X 17

ARCTOSTAPHYLOS Manzanita, Bearberry (pis. 777,778) Rounded-triangular, globose-angular, or globose, the shape often depending upon the number of nutlets adhering to each other; about 5 mm. long; walls heavy and dark brown. In A. diversi/olia, all the nutlets remain cemented to each other in a solid ball; in A. pungens they separate individually; and in others 2 or 3 nutlets generally cling to each other. ARBUTUS Madrone (pi. 779) Compressed, oval to elliptic, or irregularly angled, often concave-convex and incurved-pointed at ends; dark brown, dull, with very narrow, linear cellular reticulations; 3 X 1.5 X 1 mm.; wall rather thin.

Fig. 234. Arctostaphylos uva-ursiX 6

®

Fig. 235. Arctostaphylos andersonii X 5

«

Fig. 236. Arctostaphylos bicolor X 5

Fig. 237. Arbutus menziesii X 6

GAYLUSSACIA Huckleberry, Dangleberry (pis. 780,781) Flat or flattish, oval and somewhat wedge-shaped, with one edge thin; surface minutely rough, somewhat like sandpaper; light brown; about 2 mm. long; embryo linear. Fig. 238. Gaylussacia frondosa X 9

V A C C I N I U M Blueberry, Deerberry (pis. 782-784) Diverse; from variously angled to compressed-elliptic or compressed-oval to ellipsoid; cellular-reticulate; brown to dark brown; 1-2 mm. long; embryo linear.

Fig. 239. Vaccinium angustifolium X 13

Fig. 240. Vaccinium macrocarpon X 9

189

IDENTIFICATION

SAPOTACEAE

CLUES

Sapodilla Family

BUMELIA Bumelia (pi. 785) Ellipsoid to ovoid or globose; a cavity at the smaller end, except in B.lycioides, which has a circular scar; shiny, brown; 5-12 mm. long; wall hard, brittle, veined on the interior. Fig. 241. Bumelia lanuginosa X 3

EBENACEAE

Ebony Family

DIOSPYROS Persimmon (pi. 786) Flat-elliptic (D. virginiana, kaki), or compressed-ovoid to planoconvex (D. texana, lotus); often with one edge nearly straight; cellular lines diagonal on D. virginiana and texana, irregularly wavy and obscure in Asiatic species; brown, about 1.5 cm. long in D. virginiana", black, 1 cm. long in D. texana; wall and endosperm very hard.

OLEACEAE

Fig. 242. Diospyros virginiana X 1

Olive Family

Seeds diverse, because some are in samaras or keys (as in Fraxinus), some are in nutlets of drupes (as in Forestiera), or in a berry (as in Ligustrum), or are borne in capsules (other genera); embryo generally spatulate in fleshy endosperm. FRAXINUS Ash (pis. 788-789) Species of ash can be distinguished to some extent by the samaras, particularly as regards their size and shape and the extension of the wing along the seed body. The true seeds inside the samaras are linear-cylindric to flat-oblong, are about 1 cm. long, and generally show lengthwise wavy lines in grooves; the embryo as viewed in cross section is sandwiched between layers of endosperm.

Fig. 243. Fraxinus quadrangulata X 1

190

Fig. 244. Fraxinus excelsior X 1

Fig. 245. Fraxinus oregona X 1.5

IDENTIFICATION

CLUES

© f

FORESTIERA Waterprivet (pi. 787) Seeds (nutlets) narrowly elliptic (as in F. acuminata) or broadly elliptic to ovoid (as in other species); pointed near the ends and often arched slightly, with numerous branched, lengthwise veins in most species (lengthwise ridges and grooves in F. acuminata); about 1.5-5 mm. long.

Fig. 246. Forestiera

angusti/olia X 4

LIGUSTRUM Privet (pi. 790) Rather irregular in shape and surface; generally oval to elliptic in outline, and plano-convex, compressed, or ellipsoid; surface dull, rather scurfy and wrinkled; mainly 2-4 mm. long.

®

Fig. 247. Ligustrum vulgare X 4

LOGANIACEAE

Logania Family

GELSEMIUM Jessamine (pi. 791) Flat, elliptic, winged; 9 X 4 X 0.5 mm.; wing very thin, irregularly margined toward end; seed-body area also thin, not definitely bounded, except by many conic-oblique papillae and by darker brown color.

ASCLEPIADACEAE

Milkweed Family

ASCLEPIAS Milkweed (pi. 212) Flat, generally margined by an encircling wing, obovoid and with a terminal tuft of silky hairs (except in A. perennis); seed area slightly thicker and clearly differentiated; brown to reddish brown; 5-10 mm. long.

CONVOLVULACEAE

Fig. 248. Gelsemium sempervirens X 4

Fig. 249. Asclepias humistrata X 3

Morning-glory Family

Shape mainly rounded-triangular (Convolvulus, Ipomoea, Jacquemontia), though in some genera globose (all Cuscuta and certain Ipomoea species), ovoidtruncate (Breweria), or other shapes; surface dull, granular-rough or hairy; embryo bent (coiled, in Cuscuta), cotyledons folded, except in Cuscuta; endosperm hard, semitransparent.

191

IDENTIFICATION

CLUES

BREWERIA Breweria (pl. 213) Ovoid-truncate, with a V-shaped notch and a rounded hump at the truncate attachment end; dull, minutely rough, brown; 3-4 X 2.5 X 2.5 mm. Fig. 250. Breweria

CONVOLVULUS Morning-glory (pis. 214,215) IPOMOEA Morning-glory (pis. 217-219) These two genera are similar in having their seeds mainly rounded-triangular. However, in Convolvulus the attachment scar is nearly at right angles to the seed's long axis, whereas in Ipomoea (except in large-seeded species such as /. bona-nox, dissecta, pres-caprae, tuba) the scar is usually almost parallel to the long axis. Convolvulus seeds average smaller, 3-4 mm. long, are dull, minutely warty in C. arvensis and tricolor, and black to brown; Ipomoea seeds are more diverse: lanceolateovoid (/. quamoclit) to globose, black to brown, dull to hairy (/. fistulosa, longifolia, pandurata, pres-caprae, sagittata), and 4-12 mm. in length.

pickeringii X 3.5 +

* Fig. 251. Convolvulus incanus X 5

Fig. 252. Ipomoea lacunosa X 3.5

JACQUEMONTIA Jacquemontia (pl. 216) Rounded-triangular and truncate; minutely warty; brown; comparatively small, 2 X 1.5 X 1.5 mm.

f

Fig. 253. Jacquemontia tamnifolia X 6

CUSCUTA Dodder (pl. 220) Small, about 1 mm. across; globose to globular or roundedtriangular; dull or scurfy, brown; embryo yellowish, coiled, in semitransparent, hard endosperm. Fig. 254. Cuscuta pentagona X 15

POLEMONIACEAE

Phlox Family

Seeds generally either flattish plano-convex (Collomia, Phlox, Microsteris) or irregularly angled (Gilia, Navarretia, Polemonium); about 2.5 mm. long in the flattish type and generally smaller, 0.5-2 mm. long, in the irregularly angled forms.

192

IDENTIFICATION

CLUES

GHIA Gilia (pis. 221, 222) Irregularly angled, with the edges sharp or rounded, except G. gilioides, which is concaveovoid; mainly 0.5-1 mm. long, though G. aggregata and gilioides are about 2 mm. long; smooth or somewhat wrinkled.

Fig. 255. Gilia aggregata X 7

COLLOMIA Collomia (pi. 223) Elliptic, and plano-convex to flattish or compressed (C. grandiflora), or linear and concave-convex (C. linearis)-, all species with a lengthwise line or groove on one face; brown, dull; 2.5-3 mm. long.

Fig. 256. Gilia gracilis X 6

Fig. 257. Collomia grandiflora X 5.5

PHLOX Phlox (pi. 224) Elliptic and flattish-compressed or flattish plano-convex; with a lengthwise groove on one face; surface coarsely or finely rugose; dark brown to black; 2-3.5 mm. long. Fig. 258. Phlox pilosa X 5

BORAGINACEAE

Borage Family

Seeds (nutlets) ovoid, ovoid-angular, compressed-ovate, or other shapes; many with surface hard or bony and glossy (Lithospermum, Onosmodium, Myosotis, Amsinckia, Plagiobothrys), but many others dull, thin- to heavy-walled and some with hooked hairs; endosperm scant or none. HELIOTROPIUM Heliotrope (pi. 661) Rather diverse; globose to ovoid, concave-convex, or planoconvex; 1-3 mm. long; edges rounded (H. curassavicum and most others), or sharp-edged, acute-beaked, and with lengthwise ridges in H. indicum, hairy on the roundish back (H. angustifolium, greggii, inundatum, parviflorum, phyllostachyum, tenellum), or smooth (convolvulaceum, curassavicum, europaeum, indicum, parviflorum, and xerophyllum). Two eyelike areas on the concave or plane face distinguish H. inundatum and phyllostachyum.

Fig. 259. Heliotropiion curassavicum X 10

LITHOSPERMUM Gromwell (pis. 228,229) Ovoid-truncate, with a ridge on one side, and a broad, flattish scar at the base; surface smooth, glossy in most species (coarsely rough in L. arvense, incisum); wall hard and crusty; 2-4 mm. long.

193

IDENTIFICATION

CLUES

MYOSOTIS Forget-me-not (pi. 230) Compressed-flattish and ovate, with thin margins; dark brown to black and glossy, but attachment scar whitish; slightly more than 1 mm. long in M. laxa and virginica, and 1-2 mm. long in M. scorpioides. ECHIUM Blueweed (pi. 231) Similar to Lithospermum arvense in shape and surface; ovoid-truncate, with a large basal scar partly surrounded by a low wall or collar; surface rough; one side straight and with a low ridge. AMSINCKIA Fiddleneck (pis. 225-227) Ovate rounded-quadrangular and arched; with a linear whitish scar on the concave side and a ridge on the roundish back; rough-warty or cross-wrinkled; wall hard, brittle; 2-3 mm. long. PLAGIOBOTHRYS Popcornflower (pis. 232,233) Compressed, pointed-ovate, and slightly arched; the arched back has a low, lengthwise ridge and several crosswise ridges, while the opposite, slightly concave side has a puckered-up attachment scar, except in P. jonesii, which has a Y- or T-shaped mark on the back and small, warty pustules over much of the surface. P. shastensis and tenellus are somewhat cross-shaped. All species grayish or brownish; wall hard, brittle; 1-3 mm. long.

VERBENACEAE

Verbena Family

Seeds (nutlets or schizocarps in Verbena) diverse; the two genera included here are flattish and oblong to circular; embryo spatulate; endosperm present or lacking. VERBENA Verbena (pis. 234-236) Compressed-oblong and slightly rounded-triangular in cross section, making it somewhat 2-sided; the rounded back bearing lengthwise ridges toward lower end and a network of cross ridges below; inner face of two planes meeting in a low ridge, the surface generally covered with whitish papillae; margin bordered by a narrow flange; attachment scar whitish (in V. ciliata the scar is surrounded by a cuplike extension); 1.5-3 mm. long; endosperm lacking.

194

Fig. 260. Verbena

hnvlntn

IDENTIFICATION

CLUES

CALLICARPA Beautyberry (pl. 792) Elliptic,flatfishor concave-convex, narrowly margined on the concave side and with a central attachment scar; white to light brown; 1.5-2.5 mm. long.

LABIATAE

Mint Family

t

Fig. 261. Callicarpa americana X 10

Seeds (nutlets) generally rounded-triangular (because they are borne in tight groups of 4, or sometimes 3); surface smooth to ridged or horny; wall thin and brittle to thick and woody; embryo spatulate; endosperm scant or none. TEUCRIUM Germander (pl. 237) Globose rounded-triangular, the back (outer side) coarsely reticulate, with low ridges, and the inner side with a large, roundish scar margined by a lighter area; wall thick, woody; 1.5-2.5 mm. long. Fig. 262. Teucrium canadense X 13 TRICHOSTEMA Bluecurls (pl. 238) Ovoid to oblong, or globose rounded-triangular, the back (outer side) reticulate-ridged in T. dichotomum and lanatum, and bearing finger-like projections and pubescence in T. lanceolatum; a large, roundish scar on the inner side; 1-4 mm. long. Fig. 263. Trichostema dichotomum X SCUTELLARIA Skullcap (pl. 239) Diverse; globose and covered with dark brown bracts or scales in S. pilosa and integrifolia; other species circular in outline, with two faces, one of them more rounded; S. galericulata and lateriflora are yellowish, with a pebbly-warty surface and a conspicuous "umbilicus" on the inner face; S. parvula is like the upper part of a dark toadstool, partly covered with small, roundish warts; 1-2 mm. across.

HEDEOMA False Pennyroyal (pl. 241) Compressed-oblong (H. ciliata, hispida, nana) to subglobose-compressed (H. pulegioides) or rounded-triangular; minute, about 1 mm. long; finely cellular-reticulate; most species brownish, but H. pulegioides black. MONARDA Beebalm (pl. 242) Oblong-elliptic and compressed-triangular, with a wedge-shaped attachment area and a small, whitish, mouthlike scar; smooth; 1.5-2 mm. long.

195

IDENTIFICA TION CL UES

PRUNELLA Selfheal (pi. 240) Ovoid and compressed-triangular, tipped with white at the base, and the shiny, brown surface margined with darker brown lines and having a pair of central lengthwise lines; 2 X 1 X0.5 mm. L A M I U M Henbit (pi. 245) Elongate-ovoid, and rounded-triangular in section; brownish or grayish and mottled with silvery white; 2 X 1 X 0.5 mm. Fig. 264. Lamium amplexicaule X 10

SALVIA Sage (pis. 243,244) Oblong, elliptic, or ovoid compressed-triangular, to globose (S. officinalis)-, surface generally marbled with streaks or netted lines; gray, brownish, or black; 2-5 mm. long. LYCOPUS Bugleweed (pi. 662) Oblong-ovoid and compressed-triangular, with the top truncate and irregularly notched (L. americanus, uniflorus, virginicus), or rounded (L. europaeus, lucidus, rubellus); a small, white mouth at the base and a marginal flange; brownish with goldlike globules on the inner face; 1-1.5 mm. long. M E N T H A Mint (pi. 663) Globose to ovoid compressed-triangular, wedge-shaped at the base; brown, smooth, dull; minute, 1 mm. long or less.

SOLANACEAE

Nightshade Family

Usually medium small to large, flat or flattish, and oval to circular or reniform, but in genera such as Nicotiana and Petunia the seeds are minute and globose or subglobose; embryo coiled or bent in fleshy endosperm. S O L A N U M Nightshade (pis. 246-249) PHYSALIS Groundcherry (pis. 250,251) Flat, and oval or broadly elliptic to circular, with an obscure notch and marginal scar; surface cellular-reticulate or smooth; yellow to brown. Solanum and Physalis seeds are often confusingly similar, but usually they can be distinguished from each other. Solanum seeds vary more in size (1.5-5 mm. long), shape, and surface, whereas Physalis is about 1.5-2 mm. long and is consistently shiny, cellular-reticulate, and broadly oval.

196

IDENTIFICATION

Fig. 265. Solanum verbascifolium X 7.5

Fig. 266. Solanum dulcamara X 7.5

SCROPHULARIACEAE

CLUES

Fig. 267. Physalis heterophylla X 7.5

Figwort Family

Ordinarily minute to small; diverse in shape; surface often soft or frothy with cellular reticulations; embryo linear to spatulate in fleshy endosperm. VERBASCUM Mullein (pi. 252) Cylindric and truncate at both ends, with wavy lengthwise ridges and a dark spot at each end; resembling caterpillar droppings; about 1 mm. long or less and about one-third as thick. Fig. 268. Verbascum thapsus X 25

LINARIA Butter-and-eggs, Toadflax (pis. 253,254) Seeds diverse; in L. vulgaris they are flat, circular-winged, dark brown, about 2 mm. across, with pimple-like papillae over the central area and radial striations evident along the margin; L. canadensis seeds are dark grayish, oblong-quadrandular and somewhat wedge-shaped (both ends truncate), about 0.5 mm. long.

Fig. 269. Linaria canadensis X 30

PENSTEMON Penstemon (pi. 255) Irregularly angled, generally sharply; margins often narrowly winged; surface finely cellular; black or brownish; 1-2 mm. long.

Fig. 270. Penstemon barbatus X 9

Fig. 271. Penstemon breviflorus X 15

197

IDENTIFICATION

CLUES

BACOPA Waterhyssop (pi. 664) Oblong, and quadrangular or cylindric; truncate at both ends; minute, about 0.5 mm. long; surface cellular-reticulate in lengthwise rows, 2 or 3 rows per side; cream (B. monniera, rotundifolia) or black (fi. acuminata). Fig. 272. Bacopa acuminata X 30

VERONICA Speedwell (pi. 819) Generally oval to circular, and flat or flattish, often slightly concave-convex; the concave side has a small opening toward the center and a dark dot near the margin; yellow to brown; usually semitransparent; 0.5-1 mm. F i g 273 ~ Veronica across. V. virginica is oblong-cylindric and arched. anagallis-aquatica x 25 CASTILLEJA Paintbrush (pi. 256) Irregularly shaped, sometimes variously angled, in a mesh-bag network of coarse cells; light brown to black; about 2 mm. long; frequently the seed is loose inside the enclosing network.

®

Fig. 274. Castilleja indivisa X 23

BIGNONIACEAE

Bignonia Family

Seeds flat; bilaterally winged; embryo with large cotyledons which invest the stalk; endosperm none. TECOMA Trumpetvine (pi. 793) Wings thin, transparent, with wavy lines radiating from the center; 2-2.5 cm. long; body area circular-ovate, brownish. CATALPA Catalpa (pi. 794) Wings silky-papery, whitish, with obscure lines radiating from the central area; 2.5-3 cm. long.

PEDALIACEAE

Pedalia Family

SESAMUM Sesame (pi. 527) Flattish-ovate, with dark base and faint marginal lines and an equally faint central line on one face; white to light brown; 3 X 2 X 1 mm.

198

Fig 275

sesamum

indicum X 4.5

IDENTIFICATION

PLANTAGINACEAE

CLUES

Plantain Family

PLANTAGO Plantain (pls. 257-259) In most species, the seed is hollowed out like a boat, but it is plano-convex and elliptic in P. elongata, eriopoda, macrocarpa, maritima, and tweedyi; irregularly angled in P. major and rugeliv, 1.5-4 mm. long.

RUBIACEAE

ft

Fig- 276. Plantago rhodosperma X 7.5

Madder Family

Seeds (some of them nutlets) diverse: globose, ovoid, flat and lanceolate, or other shapes; minute to large; embryo linear to spatulate in fleshy endosperm.

CEPHALANTHUS Buttonbush (pi. 795) Cylindric-lanceolate, like miniature wooden pegs, with a dark cap on the broad end; narrow lengthwise groove on opposite sides of the 2-seeded nutlet (as evident in cross section); about 5 mm. long.

2?7 Cephalanthus

occidentals X 5

MITCHELLA Partridgeberry (pi. 820) Flattish oval-oblong; with a small hole or protrusion on one face and with fibers of the wall concentric about this point; whitish; 3 X 2 X 1 mm. DIODIA

Buttonweed (pi. 260)

Oval-oblong; D. teres is plano-convex, with a thick end topped by 3 apical bracts, and the other end thin; its flattened face is shallowly indented, and the rounded back is bristly-hairy. In D. virginiana, 2 facing seeds commonly remain attached to each other in a compressed oval-oblong body with about 10 lengthwise, broadly rounded ribs separated by grooves. The seed of D. virginiana is 6-7 mm. long, whereas that of D. teres is about half as long.

Fig. 278. Mitchella repens X 6.5

CmD

Fig. 279. Diodia teres X 6

GALIUM Bedstraw (pis. 821-823) Globose or subglobose, hollow-centered or hollowed out on one side; bristly, tuberculate, or smooth; black or dark brown; 1-3 mm. across.

199

IDENTIFICATION

Fig. 280. Galium bermudense X 6

Fig. 281. Galium trifidumX 13

CAPRIFOLIACEAE

CLUES

Fig. 282. Galium latifolium X 6

Honeysuckle Family

Seeds (some of them nutlets) diverse in shape and size, mainly woody-walled; embryo small or medium-sized, in fleshy endosperm. SAMBUCUS Elderberry (pi. 796) Elliptic-ovate and compressed rounded-triangular; generally slightly arched inward; with crosswise wrinkles; brown, dull; wall woody; 2-3 mm. long.

Fig. 283. Sambucus canadensis X 5.5

SYMPHORICARPOS Snowberry, Coralberry (pis. 797,798) Elliptic plano-convex, with rounded edges and a small, porelike opening at one end; wall tough, woody, with obscure lengthwise fibers; white to light brown; 3-4 mm. long.

Fig 284. Symphoricarpos orbiculatus X 6

LONICERA Honeysuckle (pis. 799,800) Oval to elliptic, flattish or compressed, with a notch or point at one end; often irregularly ridged and warped; finely to coarsely cellular; yellow to dark brown; wall crustose to woody; 2-5 mm. long. Fig. 285. Lonicera dioica X 4.5

VIBURNUM Viburnum (pis. 801-803) Diverse; flat or flattish and ovate, elliptic, or circular, to ovoid or globose; with rounded lengthwise ridges and grooves; wall hard but generally rather thin; 4-10 mm. long. Fig. 286. Viburnum dentatum X 4.5

200

IDENTIFICATION

CUCURBITACEAE

CLUES

Melon Family

CITRULLUS Watermelon (pi. 528) Flat, oval-ovate, with a marginal groove on each side near the base; white, black, or white with black margins; 10-15 mm. long.

CAMPANULACEAE

Campanula Family

SPECULARIA Venus Looking-glass Flattish or compressed, oval to elliptic, smooth, dull to glossy; minute, generally less than 0.5 mm. long; S. biflora is glossy light brown, and S. perfoliata is broadly oval, thick, purplish brown, and dull.

COMPOSITAE

Fig. 287. Specularla biflora X 35

Daisy Family

Seeds (achenes) diverse; many of them oblong or elongate, with or without a terminal ring (pappus) of hairs or scales; characteristics of the p a p p u s are often useful for identification; embryo with well-developed cotyledons and a broad stalk having a truncate top; endosperm none.

VERNONIA Ironweed (pi. 665) Body oblong, coarsely ridged, light brown, 3-4 mm. long; pappus generally purpletinged and longer than the body; the hairs short-plumose with very fine secondary hairs; base of pappus encircled by a series of semitransparent, flat, hairlike scales. LIATRIS Gayfeather (pi. 261) Similar to Vernonia in plumose pappus, which is purple-tinged in some species; no pappus scales; body generally black, hairy, narrowed toward base; about 5 mm. long. EUPATORIUM Boneset (pi. 666) Body oblong, 4- or 5- sided, black, tapering toward base and often white-tipped; length variable, from 1.5 mm. (as in E. coelestinum, mikanioides, urticaefolium) to 5 mm.; pappus of delicate, stiff white hairs, which are minutely plumose.

201

IDENTIFICA

CHRYSOPSIS

TION CL UES

Goldaster (pi. 263)

Body flat, ovate to elliptic-oblong; hairy; light-colored to brownish (C. graminifolia); 2-3 mm. long; pappus double, hairs of innerringbrownish, stiff, minutely plumose, outer ring composed of short, hairlike scales.

GRINDELIA

Gumweed, Rosinweed (pi. 262)

No pappus; body oblong, compressed or flat; truncate at top, narrowed toward base; often arched sideways, with one edge straight or concave and the other convex; surface marked by lengthwise lines or irregular ridges; straw-colored or brown; length 2 mm. (G. squarrosa) to 5 mm.

GUTIERREZIA

Snakeweed (pi. 264)

Body oblong-ellipsoid; small (1-2 mm. long); dark, clothed with whitish hairs; pappus a ring of scales.

HETEROTHECA

Heterotheca (pi. 265)

Very similar to Chrysopsis in having a double pappus with brownish pappus bristles, surrounded by hairlike scales, and in its flat, oblong-attenuate, light-colored, hairy body. The ray-flower achenes of Heterotheca are distinct in being smooth, compressedtriangular, and without pappus.

SOLI DAGO Goldenrod (pis. 266,267) ASTER Aster (pis. 667,824) ERIGERON Fleabane (pi. 268) Seeds of these extensive genera overlap considerably in size, shape, and other characteristics. The seed body is small, ordinarily 1-3 mm. long, oblong-cylindric to compressed oblong-elliptic, and with a tapering base, hairy or smooth; pappus is a ring of white, minutely plumose bristles, which are often wavy near their base. Solidago seeds average smaller in their body (generally 1-2 mm. long) than Aster, and are more consistently hairy and oblong-cylindric; Aster seeds are rather distinct from Solidago in commonly being compressed and in having lengthwise ridges on the fairly numerous species which have smooth or nearly smooth seeds. Erigeron seeds, except for species like E. salsuginosus, which are comparatively large (body 2.5 mm. long) and coarse, can usually be distinguished from those of Aster and Solidago by the delicate pappus on a smaller body (1-1.5 mm. long), which is flattish, yellow to brown. Erigeron seeds vary in pubescence from sparsely short-hairy to densely hairy.

IVA

Marshelder, Sumpweed (pis. 668,669)

Flattish or compressed, obovate to broadly oblanceolate and truncate at the top; black or brown; dull and often scurfy; wall interior white; 2-5 mm. long.

202

IDENTIFICATION CLUES

AMBROSIA Ragweed (pis. 269-272) Obovoid to oblanceolate, generally with spines near the top, the spines often buttressed by ridges; 2-10 mm. long; usually grayish, but on worn seeds of the common species, A. artemisiaefolia, the gray coat gives way to a shiny brown one, which in turn overlies successive black and white layers.

Fig. 288. Ambrosia artemisiaefolia

RUDBECKIA Coneflower, Black-eyed-Susan (pis. 273,274) Oblong to linear and generally 4-sided (cylindric or compressed-cylindric in R. amplexicaule, which is distinct in its fine cross wrinkles on a black coat); upper end truncate; sides usually with fine lengthwise lines; short pappus scales present or absent; gray-brown to black; 2-8 mm. long. RATI Bl DA Pra i rie-coneflo wer (pl. 275) Flat to compressed, oblong, sharply truncate at top and rounded at base; obscure lengthwise lines on black or grayish black surface; with or without a pair of pappus scales; 2-3 mm. long. R. peduncularis seeds are margined with a fringe of flat, finger-like projections. HELIANTHUS Sunflower (pis. 276-278) Compressed or flattish, oblong; top truncate and base narrowed; generally grayish, with dark lengthwise streaks and mottlings; often pubescent, especially near the top, with stiff, upward-directed hairs; attachment area shiny; mostly about 5 mm. long, but in the cultivated form of H. annttus the length may exceed 1 cm. ENCELIA Encelia (pis. 279.280) Flat, broadly-oblanceolate; a dense fringe of long white hairs on the margins and with or without hairs elsewhere; 5-10 mm. long; E. farinosa is emarginate at the top. VERBESINA

Crownbeard (pis. 281-283)

Flat to compressed and oval to oblong; most species are wing-margined and have a deep apical notch which is bordered by 2 obscure awns, but V. occidentalis is nearly oblong, wingless, and has 2 long, hornlike awns; about 5 mm. long. M A D I A Tarweed (pis. 284,285) Flattish-oblanceolate and often arched sideways; with fine lengthwise lines; black or grayish; 3-4 mm. long.

203

IDENTIFICATION

CLUES

HEMIZONIA Tarweed (pis. 286,287) Rounded-triangular and generally with its broad face arched inward; style base knoblike; black or grayish; 2-3 mm. long. COREOPSIS Coreopsis (pi. 288) Flat orflatfish,and either circular, oval, or oblong; often arched inward like a curved potato chip; wing-margined in certain species (C. gladiata has finger-like marginal projections) and frequently tuberculate on one or both faces; 1.5-6 mm. long. BIDENS Sticktight (pis. 670,671) Linear and several-sided, to flat-oblong or flat-oblanceolate; 2 to 4 awns, which are generally barbed, extend upward from the top, and some species have barbs on the margins of the seed body; brown to black; entire seed, including awns, 0.5-2 cm. long. HELENIUM Sneezeweed (pis. 290,291) Body obconic or oblong and several-sided; crowned with about 6 semitransparent, broad, tapering pappus scales, which are frequently tipped by awns; entire seed 2-7 mm. long. H. tenuifolium seeds are obconic and have long hairs extending upward from the base. GAILLARDIA Gaillardia (pi. 289) Body obconic; densely coated with stiff hairs; crowned by 6 or more long-awned pappus scales; brown; entire seed 5-7 mm. long. ANTHEMIS Mayweed (pi. 292) Usually oblong and 4-sided; crowned by a cup in A. arvensis and tinctoria; A. cotula is club-shaped, with about 8 lengthwise, rather knobby ridges, and has a rounded top; 1.5-2 mm. long. ACHILLEA Yarrow (pi. 293) Flat-oblong; truncate at the top and narrowed to a rounded base; the thin margins whitish and the body dark; pappus none; about 2 mm. long. CHRYSANTHEMUM Oxeye Daisy, Chrysanthemum (pi. 294) Cylindric; with numerous lengthwise ridges; C. coccineum and uliginosum are cupshaped at the top; C. leucanthemiun and maximum are either rounded or truncate at the top, have a prominent, knoblike style base, and a body striped with light-colored ridges alternating with dark lines; about 2-3 mm. long.

204

IDENTIFICATION

CLUES

CIRSIUM Thistle (pis. 295,296) Body compressed, lanceolate-oblong; top cup-shaped and usually tilted slightly sideways; body narrowed to a rounded base and marked by obscure lengthwise lines; gray to dark brown, smooth; 3-6 mm. long; pappus composed of many long, plumose bristles, which are united at the base into a readily detached ring. CENTAUREA Starthistle, Centaurea (pis. 297-299) Body cylindric or compressed-cylindric, elliptic-obovate or elliptic-oblong; top truncate; base asymmetric and notched, or in some species, the base is narrowed and arched like a hook; pappus white or tawny, persistent or deciduous, composed of stiff, bristlelike scales, making the seed look like a shaving brush; body smooth, gray to black; 2.5-5 mm. long. SILYBUM Milk Thistle (pi. 300) Body compressed oblong-lanceolate; top cup-shaped, tilted slightly sideways, and enclosing a large, knoblike style base; body black with white collar; 7 X 3 X 2 mm.; pappus deciduous. CICHORIUM Chicory (pi. 301) Slightly compressed and arched-oblong; top truncate and fringed with a ring of stubby scales; body narrowed into a rounded base and minutely cross-wrinkled; brown or mottled; 2 X 1 X 0.75 mm. SERINEA Serinea (pi. 302) Elliptic-cylindric; narrowed toward base; marked with about 12 lengthwise, finely cross-wrinkled ridges; reddish brown or purplish brown; about 1 mm. long and less than half as wide; pappus none. TARAXACUM Dandelion (pi. 303) Body flattish-oblanceolate and somewhat 4-angled; narrowed toward both ends; tubercles or teeth near the upper end of the lengthwise ridges; yellow or straw-colored; 3-4 mm. long; the pappus delicate, white, and appearing like an inverted umbrella on a long handle. SONCHUS Sowthistle (pi. 304) Body flat, and elliptic or lanceolate-elliptic; similar to Lactuca in shape, ridging, and minute wrinkling, but smaller, about 3 mm. long, and more obtuse at ends; brown or reddish brown; pappus bristles long, soft, delicate, deciduous.

205

IDENTIFICATION

CLUES

LACTUCA Wild-lettuce (pis. 305,306) Body flat, elliptic to lanceolate; pointed near both ends, though in L. spicata the apical end broadens again into a terminal disc; most species have about 8 lengthwise ridges, which are finely cross-marked, but L. canadensis has only 1 conspicuous ridge and isfinelycross-wrinkled over the whole surface, while L. spicata has 2 ridges and is similarly cross-marked; pappus delicate, deciduous; body grayish brown to black, except in L. sativa, which is cream-colored; body 4-5 mm. long.

HIERACIUM Hawkweed (pi. 307) Body cylindric; top truncate; body narrowed toward base and marked by about 10 distinct lengthwise ridges, which in some species are finely cross-marked; dark reddish browntoMack; 2-4 mm. long; pappus bristles stiff, delicate, in a single series.

206

Selected Bibliography

Family Characters Investigations in Seed Classification by Family Characteristics. Duane Isely. Iowa Agr. Exp. Sta. Res. Bull. 351. 1947. Seed Characters of Selected Plant Families. David S. McClure. Iowa State Coll. Jour. Sci. 31:649-682. 1957.

Weed Seeds Seed Drawings. Pis. 1-15. U. S. Dept. Agr., Office of Information, Division of Photography. [Fifteen sheets of photograph reproductions of excellent seed drawings, twenty-four species per page.] Unkrautsamen [Weed Seeds]. Emil Korsmo. Oslo, Grondahl & Sons, 1935.

Woody Plants Graines et plantules des conifères. R. Hickel. Macon, France, 1911, 1914. Trees: The Yearbook of Agriculture, 1949. Washington, U. S. Dept. Agr., 1949. Woody-Plant Seed Manual. U. S. Dept. Agr. Misc. Publ. 654. 1948.

Comparative Morphology The Comparative Internal Morphology of Seeds. Alexander C. Martin. Am. Midi. Nat. 36:513-660. 1946.

Seed Testing Manual for Testing Agricultural and Vegetable Seeds. U. S. Dept. Agr. Handbook 30. 1952.

Families and Genera ATRIPLEX

An Illustrated Flora of the Pacific States. Leroy Abrams. Vol. 2. Stanford, Calif., Stanford Univ. Press, 1944. BETULA

A Seed Key for Five Northeastern Birches. Frank E. Cunningham. Jour. For. 55:844845.1957.

207

BIBLIOGRAPHY

BRASSICA

Distinguishing Species of Brassica by Their Sgeds. Albina F. Musil. U. S. Dept. Agr. Misc. Publ. 643. 1948. Seeds and Seedlings of the Genus Brassica. Jean M. McGugan. Canad. Jour. Res., Sec. C, 26:520-587. 1948. Seeds of Commercial Species of Brassica. Albina F. Musil. Proc. Assn. Offic. Seed Anal. 34:132-138. 1942. CAREX

North American Cariccae. K. K. MacKenzie. New York, N. Y. Bot. Gard., 1941. CHENOPODIUM

Seeds of the North American Species of Chenopodium. Sister M. Angelita Conley. Master's Thesis, Univ. Notre Dame. 1938.

COMPOSITAE

Akenes of Some Compositae. Anita Mary Blake. N. Dak. Agr. Coll. Bull. 218. 1928. CRUCIFERAE

Seeds of the Cruciferae of Northeastern North America. Margaret R. Murley. Am. Midi. Nat. 46:1-81. 1951. CUSCUTA Seeds of Dodder Occurring with Crop Seeds. Albina F. Musil. Washington, U. S. Dept. Agr., Bur. PI. Ind., Soils and Agr. Eng., 1944. CYPERUS

A Revision of the Subgenus Eucyperus Found in the United States. Sister M. Vincent de Paul McGivney. Cath. Univ. Am. Publ., Biol. Ser., 26. 1928. ELEOCHARIS

A Flora of the Marshes of California. Herbert L. Mason. Berkeley and Los Angeles, Univ. Calif. Press, 1957. [Cited, after first reference, as Mason.] Monographic Studies in the Genus Eleocharis. H. K. Svenson. Rhodora 31:121-135, 152-163, 167-191, 199-219, 224-242; 34:193-203, 215-227; 36:377-389; 39:210-231, 236-273; 41:1-19, 43-77, 90-110. 1929, 1932, 1934, 1937, 1939. ERODIUM

Alfileria (Filaree) Seed. William A. Dayton. Rhodora 39:323-325. 1937. EUPHORBIA

Euphorbia, Subgenus Chamaesyce, in Canada and the United States, Exclusive of Southern Florida. Louis Cutter Wheeler. Rhodora 43:97-154, 168-205, 223-286. 1941. GERANIACEAE

A Seed Key to Fourteen Species of Geraniaceae. Margaret R. Murley. Proc. Iowa Acad. Sei. 51:241-246. 1944. GRAMINEAE

Manual of the Grasses of the United States. A. S. Hitchcock. 2d ed., rev. by Agnes Chase. U. S. Dept. Agr. Misc. Publ. 200. 1950.

208

BIBLIOGRAPHY

LEGUMINOSAE

Anatomical Characters of the Seeds of Leguminosae, Chiefly Genera of Gray's Manual. L. H. Pammel. Trans. Acad. Sci. St. Louis 9:91-263. 1899. POLYGONUM

Identifying Polygonum Seeds. Alexander C. Martin. Jour. Wildl. Mgmt. 18:514-520. 1954. POTAMOGETON

Identifying Pondweed Seeds Eaten by Ducks. Alexander C. Martin. Jour. Wildl. Mgmt. 15:253-258. 1951. RHYNCHOSPORA

Rhynchospora, Section Eurhynchospora, in Canada, the United States, and the West Indies. Shirley Gale. Rhodora 46:89-134, 159-197, 207-249, 255-278. 1944. UMBELLIFERAE

Umbelliferae in Iowa, with Seed Keys. Margaret R. Murley. Iowa State Coll. Jour. Sci. 20:349-364. 1946.

209

Index

This index is based primarily on genus and family names, both scientific and common. Photographic plates 308-510 are indicated by italic numbers because they are duplicates of plates in the preceding series, 1-307. Abies, pis. 678, 679; fig. 6; p. 125 Abronia, pis. 69, 383; fig. 88; p. 153 Acacia, Acacia, pis. 731, 732; p. 167 Acalypha, pis. 180-182, 368; fig. 180; p. 176 Acer, pis. 752-755; fig. 193; p. 178 Aceraceae, p. 178 Achillea, pi. 293; p. 204 Aeschynomene, pis. 144, 481; fig. 161; p. 171 Agrimonia, pis. 111,330; p. 167 Agrimony, pis. I l l , 330; p. 167 Agropyron, pi. 10; p. 133 n. 3 Agrostemma, pis. 80,446; fig. 99; p. 155 Agrostis, pi. 16; p. 133 n. 3 Aizoaceae, p. 154 Alder, pi. 690; p. 143 Alfalfa, pi. 522; p. 169 Alismaceae, p. 132 Alnus, pi. 690; fig. 59; p. 143 Alsike, pis. 127,477 Amaranthaceae, p. 153 Amaranthus, pis. 65-67,436, 644, 645; fig. 86; p. 153 Amaryllidaceae, p. 141 Amaryllis family, p. 141 Ambrosia, pis. 269-272, 329, 433; fig. 288; p. 203 Amelanchier, pi. 717; fig. 131; p. 165

Amorpha, pi. 736; fig. 155; p. 170 Ampelopsis, pi. 765; fig. 202; p. 181 Amphicarpa, pi. 815; fig. 167; p. 173 Amsinckia, pis. 225-227,413; p. 194 Anacardiaceae, p. 177 Anacharis (Elodea), pi. 543; fig. 22; p. 132 Andropogon, pis. 42,43, 308; p. 133 n. 3 Aneilema, Aneilema, pi. 626; fig. 44; p. 139 Anemone, Anemone, pis. 87, 317; fig. 113; p. 159 Anthemis, pis. 292,374; p. 204 Apios, pi. 814; p. 172 Apple, pi. 712; p. 164 Aquifoliaceae, p. 178 Arabis, pis. 105, 106, 324; p. 163 Aralia, Aralia, pis. 770, 771; fig. 225; p. 187 Aralia family, p. 187 Araliaceae, p. 187 Arbutus, pi. 779; fig. 237; p. 189 Arctostaphylos, pis. Ill, 778; figs. 234236; p. 189 Argemone, pis. 90,359; fig. 120; p. 161 Aristida, pi. 21; p. 133 n. 3 Aronia, pi. 715; fig. 133; p. 165 Arrowhead, pis. 623-625; p. 132 Arrow-wood, pi. 801 Asclepiadaceae, p. 191 Asclepias, pis. 212, 320; fig. 249; p. 191

211

INDEX

Ascyrum, pi. 818; p. 183 Ash, pis. 788, 789; p. 190 Aster, Aster, pis. 667, 824; p. 202 Astragalus, pis. 141, 142, 484; fig. 160; p. 171 Atriplex, pis. 60, 61, 312, 435; fig. 82; p. 152 Avena, pis. 12, 514; p. 133 n. 3 Avens, pis. 110, 325; p. 167 Bacopa, pi. 664; fig. 272; p. 198 Balsam family, p. 179 Balsaminaceae, p. 179 Barbarea, pis. 102, 103,469; p. 163 Barberry, pis. 88, 402; p. 159 Barberry family, p. 159 Barley, pis. 11, 513; p. 133 n. 3 Bayberry, pi. 686; p. 142 Beadruby, pi. 807; p. 140 Beakrush, pis. 597, 598; p. 137 Bean, pis. 163,482, 525; p. 173 Bean family, p. 167 Bearberry, pi. 777; p. 189 Beautyberry, pi. 792; p. 195 Bedstraw, pis. 821-823; p. 199 Beebalm, pis. 242,497; p. 195 Beech, pi. 691; fig. 60; p. 144 Beech family, p. 143 Berberidaceae, p. 159 Berberis, pis. 88, 89, 402, 407; fig. 114; p. 159 Berchemia, pi. 758; fig. 200; p. 180 Bermudagrass, pi. 24; p. 133 n. 3 Betula, pi. 689; fig. 58; p. 143 Betulaceae, p. 142 Bidens, pis. 670, 671; p. 204 Bignonia family, p. 198 Bignoniaceae, p. 198 Bindweed, pis. 214,411 Birch, pi. 689; p. 143 Birch family, p. 142 Bird Rape, pi. 101 Bittersweet, pi. 750; p. 178 Bittersweet family, p. 178 Bitterweed, pis. 290, 350 Black Locust, pi. 737; p. 170 Blackberry, p. 166 Black-eyed-Susan, pis. 273,396; p. 203 Blackgum, pi. 769; p. 188 Blackhaw, pi. 803

212

Blueberry, pis. 782,783; p. 189 Bluecurls, pis. 238, 333; p. 195 Blue-eyed-grass, pi. 630; p. 142 Bluegrass, pis. 7, 8; p. 133 n. 3 Bluestem, pis. 43, 308; p. 133 n. 3 Blueweed, pis. 231,414; p. 194 Boehmeria, pi. 810; fig. 67; p. 146 Boerhaavia, pis. 68, 423; fig. 87; p. 153 Boneset, pi. 666; p. 201 Borage family, p. 193 Boraginaceae, p. 193 Bouncingbet, pi. 84; p. 156 Bouteloua, pis. 25, 26, 405; p. 133 n. 3 Boxelder, pi. 754 Brasenia, pi. 554; fig. 108; p. 158 Brassica, pis. 100, 101, 364; p. 163 Breweria, Breweria, pis. 213, 382; fig. 250; p. 192 Bristlegrass, pis. 38-40; p. 133 n. 3 Bromus, pis. 1-3; fig. 24; p. 133 n. 3 Broomsedge, pi. 42; p. 133 n. 3 Browntop, pi. 574; p. 133 n. 3 Buckbrush, pi. 760; p. 180 Buckhorn, pis. 258, 502 Buckthorn, pis. 756, 757; p. 179 Buckthorn family, p. 179 Buckwheat, pi. 521; p. 151 Buckwheat family, p. 147 Buffaloberry, pi. 768; p. 185 Buffalobur, pis. 249,492 Bugleweed, pi. 662; p. 196 Bullgrass, pi. 32; p. 133 n. 3 Bulrush, pis. 599-612; p. 137 Bumelia, Bumelia, pi. 785; fig. 241; p. 190 Bunchberry, pi. 772 Bundleflower, pis. 112, 113, 395, 462; p. 167 Burclover, pis. 125, 480; p. 169 Burreed, pis. 621,622; p. 127 Burreed family, p. 127 Butter-and-eggs, pis. 254,319; p. 197 Buttercup, pis. 647-652; p. 158 Buttercup family, p. 158 Butterflypea, pis. 157,475; p. 172 Buttonbush, pi. 795; p. 199 Buttonweed, pis. 260, 342; p. 199 Cactaceae, p. 184 Cactus, pis. 205, 206, 379, 487; pp. 184, 185

INDEX

Cactus family, p. 184 Calandrinia, pis. 73,439; fig. 93; p. 154 California-poppy, pis. 91, 358; p. 161 Callicarpa, pi. 792; fig. 261; p. 195 Caltrop, pis. 171,496; p. 175 Caltrop family, p. 175 Campanula family, p. 201 Campanulaceae, p. 201 Campion, pis. 83,445; p. 156 Canada Thistle, pis. 295, 392 Canarygrass, pis. 516, 566; p. 133 n. 3 Caper family, p. 162 Capparidaceae, p. 162 Caprifoliaceae, p. 200 Capsella, pis. 98, 498; p. 162 Carex, pis. 616-619; figs. 42, 43; p. 138 Carpetweed, pis. 72,448; p. 154 Carpetweed family, p. 154 Carpinus, pi. 687; fig. 57; p. 143 Caryophyllaceae, p. 155 Cashew family, p. 177 Cassia, pis. 114, 115, 461, 463; figs. 145147; p. 168 Castilleja, pis. 256, 376; fig. 274; p. 198 Catalpa, Catalpa, pi. 794; p. 198 Catchfly, pis. 81, 82,444; p. 156 Cattail, pi. 620; p. 126 Cattail family, p. 126 Ceanothus, pis. 760, 761; fig. 198; p. 180 Celastraceae, p. 178 Celastrus, pi. 750; fig. 191; p. 178 Celtis, pis. 699, 700; fig. 63; p. 145 Cenchrus, pi. 41; p. 133 n. 3 Centaurea, Centaurea, pis. 297-299, 349, 504; p. 205 Centella, Centella, pi. 659; fig. 226; p. 187 Centrosema, pis. 157,475; p. 172 Cephalanthus, pi. 795; fig. 277; p. 199 Cerastium, pis. 79,493; fig. 98; p. 155 Ceratophyllaceae, p. 157 Ceratophyllum, pi. 549; fig. 104; p. 157 Cereus, pis. 204, 441; p. 184 Chamaecrista, pis. 117, 118,464; figs. 148, 149; p. 168 Cheatgrass, pi. 3; p. 133 n. 3 Checkermallow, pis. 192,490; p. 181 Chenopodiaceae, p. 151 Chenopodium, pis. 56-58, 434; figs. 78-80; p. 151 Cherry, pis. 726-729; p. 166

Chess, pi. 1; p. 133 n. 3 Chickweed, pis. 78, 79,443,493; p. 155 Chicory, pis. 301,391; p. 205 Chocolate family, p. 182 Chocolateweed, p. 182 Chokeberry, pi. 715; p. 165 Chrysanthemum, Chrysanthemum, pis. 294, 387; p. 204 Chrysopsis, pis. 263, 348; p. 202 Chufa, pi. 582 Cichorium, pis. 301, 391; p. 205 Cinquefoil, pis. 108, 109, 485; p. 166 Cirsium, pis. 295, 296, 392; p. 205 Citrullus, pi. 528; p. 201 Cladium, pi. 615; fig. 41; p. 138 Clammy weed, pis. 95, 452; p. 162 Cleome, pis. 94, 95, 453; fig. 125; p. 162 Clover, pis. 126-130,477; p. 169 Cocculus, pi. 812; fig. 115; p. 159 Cockle, pis. 80,466; p. 155 Coffeeweed, pis. 143,390; p. 170 Collomia, Collomia, pis. 223,500; fig. 257; p. 193 Commelina, pis. 46, 47, 381, 494; fig. 45; p. 139 Commelinaceae, p. 138 Compositae, p. 201 Condalia, Condalia, pi. 759; fig. 199; p. 180 Coneflower, pi. 274; p. 203 Convolvulaceae, p. 191 Convolvulus, pis. 214, 215,^//,* fig. 251; p. 192 Coontail, pi. 549; p. 157 Coontail family, p. 157 Copperleaf, pis. 180-182,368; p. 176 Coralberry, pi. 797; p. 200 Cordgrass, pi. 565; p. 133 n. 3 Coreopsis, Coreopsis, pis. 288, 322; p. 204 Corispermum, pis. 62, 318; fig. 83; p. 152 Cornaceae, p. 188 Cornbind, pis. 55,421 Cornus, pis. 772-775; figs. 229-231; p. 188 Cotoneaster, pi. 718; fig. 134; p. 165 Cowpea, pi. 524; p. 172 Crabgrass, pis. 27-29, 311; p. 133 n. 3 Crataegus, pis. 719, 720; fig. 135; p. 165 Creosote, pi. 738; p. 175 Crotalaria, Crotalaria, pis. 119, 120, 483; fig. 150; p. 168

213

INDEX

Croton, pis. 174-178, 357, 384, 459; figs. 177, 178; p. 176 Crowberry, pi. 739; p. 177 Crowberry family, p. 177 Crowfootgrass, pis. 23,476; p. 133 n. 3 Crownbeard, pis. 281-283, 323, 327; p. 203 Cruciferae, p. 162 Cucurbitaceae, p. 201 Cuscuta, pis. 220,362; fig. 254; p. 192 Cutgrass, Giant, pi. 569; p. 133 n. 3 Cutgrass, Rice, pi. 567; p. 133 n. 3 Cycloloma, pis. 59, 315, 454; fig. 81; p. 151 Cynodon, pi. 24; p. 133 n. 3 Cyperaceae,p. 135 Cyperus, pis. 45,419, 578-582; figs. 25, 26; p. 136 Dactyloctenium, pis. 23, 476; fig. 24; p. 133 n. 3 Daisy family, p. 201 Daisy, Oxeye, pis. 294, 387; p. 204 Dandelion, pis. 303, 399; p. 205 Dangleberry, pi. 781; p. 189 Daucus, pis. 211,336; fig. 228; p. 188 Dayflower, pis. 46,47, 381, 494; p. 139 Dayflower family, p. 138 Decodon, pi. 656; p. 185 Deerberry, pi. 784; p. 189 Deervetch, pis. 131-135, 353, 398, 468; p. 169 Delphinium, pis. 85, 86, 335, 430; fig. 112; p. 159 Descurainia, pi. 104; p. 163 Desmanthus, pis. 112, 113, 395, 462; fig. 143; p. 167 Desmodium, pis. 145-147, 478; figs. 162, 163; p. 171 Digitarla, pis. 27-29,311; p. 133 n. 3 Diodia, pis. 260,342; fig. 279; p. 199 Diospyros, pi. 786; fig. 242; p. 190 Distichlis, 563, 564; p. 133 n. 3 Dock, pis. 52,422; p. 147 Dodder, pis. 220, 362; p. 192 Dogwood, pis. 773-775; p. 188 Dogwood family, p. 188 Douglasfir, pi. 681; p. 126 Doveweed, pis. 174-178,357, 384, 459; p. 176 Dropseed, pis. 19, 20,507; p. 133 n. 3

214

Dulichium, Dulichium, pi. 583; fig. 27; p. 136 Ebenaceae, p. 190 Ebony family, p. 190 Echinocactus, pis. 206, 379; figs. 218-220; p. 185 Echinochloa, pis. 575-577; fig. 24; p. 133 n. 3 Echium, pis. 231,414; p. 194 Eelgrass, pi. 542; p. 131 Eichhornia, pi. 548; p. 139 Elaeagnaceae, p. 185 Elaeagnus, pi. 767; p. 185 Elaeagnus family, p. 185 Elderberry, pi. 796; p. 200 Eleocharis, pis. 584-594; figs. 28-30; p. 136 Eleusine, pis. 22,416; fig. 24; p. 133 n. 3 Elm, pis. 697,698; fig. 62; p. 145 Elm family, p. 145 Elodea (synonym of Anacharis), Elodea, p. 132 Empetraceae, p. 177 Empetrum, pi. 739; fig. 186; p. 177 Encelia, Encelia, pis. 279, 280, 326, 338; p. 203 Eragrostis, pis. 9,365; p. 133 n. 3 Eremocarpus, pis. 179, 408; fig. 179; p. 176 Ericaceae, p. 188 Erigeron, pis. 268, 343; p. 202 Eriogonum, Eriogonum, pis. 49, 50, 403; fig. 69; p. 147 Erodium, pis. 168, 169, 340, 373, 400; fig. 173; p. 174 Eschscholtzia, pis. 91,358; fig. 121; p. 161 Euonymus, pi. 751; fig. 192; p. 178 Eupatorium, pi. 666; p. 201 Euphorbia, pis. 185-190, 367, 426, 449; figs. 183-185; p. 177 Euphorbiaceae, p. 175 Evening-primrose, pis. 207, 208, 313, 429; p. 186 Evening-primrose family, p. 185 Fagaceae, p. 143 Fagopyrum, pi. 521; fig. 77; p. 151 Fagus, pi. 691; fig. 60; p. 144 Falsemallow, pis. 193, 489; p. 181 Falsenettle, pi. 810; p. 146

INDEX

False Pennyroyal, pis. 241, 366; p. 195 False Solomonseal, pi. 805; p. 140 Fescue, pis. 4, 5; p. 133 n. 3 Festuca, pis. 4, 5; p. 133 n. 3 Fiddleneck, pis. 225-227,413; p. 194 Figwort family, p. 197 Filaree, pis. 168, 169,340, 373,400; p. 174 Fimbristylis, Fimbristylis, pis. 595, 596; figs. 31,32; p. 136 Fir, pis. 678, 679; p. 125 Firethorn, pi. 718; p. 165 Flatsedge, pis. 45, 419, 578-581; p. 136 Flax, pis. 164,491, 526; p. 174 Flax family, p. 174 Fleabane, pis. 268, 343; p. 202 Flowering Dogwood, pi. 775 Forestiera, pi. 787; fig. 246; p. 191 Forget-me-not, pis. 230,440; p. 194 Four-o-clock family, p. 153 Fragaria, pis. 107,486; fig. 139; p. 166 Fraxinus, pis. 788, 789; figs. 243-245; p. 190 Frogbit family, p. 132 Gaillardia, Gaillardia, pis. 289, 351; p. 204 Galactia, pis. 162,474; fig. 168; p. 173 Galium, pis. 821-823; figs. 280-282; p. 199 Gaultheria, pi. 776; fig. 233; p. 189 Gaura, Gaura, pis. 210,424; p. 186 Gayfeather, pis. 261,346; p. 201 Gaylussacia, pis. 780, 781; fig. 238; p. 189 Gelsemium, pi. 791; fig. 248; p. 191 Geraniaceae, p. 174 Geranium, Geranium, pis. 166, 167, 370; fig. 172; p. 174 Geranium family, p. 174 Germander, pis. 237,361; p. 195 Geum, pis. 110, 325; p. 167 Giantcactus, pis. 204,441; p. 184 Giant Cutgrass, pi. 569; p. 133 n. 3 Gilia, Gilia, pis. 221, 222, 432; figs. 255, 256; p. 193 Globemallow, pis. 191,488; p. 181 Glyceria, pis. 560, 561; p. 133 n. 3 Glycine (Soja), pi. 523; p. 172 Goldaster, pis. 263, 348; p. 202 Goldenrod, pis. 266, 267, 347; p. 202 Goosefoot, pis. 58,434; p. 151 Goosefoot family, p. 151 Goosegrass, pis. 22,416; p. 133 n. 3

Grama, pis. 25, 26,405; p. 133 n. 3 Gramineae, pp. 133 and n. 3, 135 Grape, pis. 762-764; p. 181 Grape family, p. 180 Grass family, pp. 133 and n. 3, 135 Greenbrier, pis. 684, 685; p. 141 Grindelia, pis. 262,389; p. 202 Gromwell, pis. 228, 229,378; p. 193 Groundcherry, pis. 250, 251,457; p. 196 Groundnut, pi. 814; p. 172 Gumweed, pis. 262, 389; p. 202 Gutierrezia, pis. 264,388; p. 202 Hackberry, pis. 699,700; p. 145 Haloragidaceae, p. 186 Hamamelidaceae, p. 163 Hamamelis, pi. 710; fig. 126; p. 163 Hawkweed, pis. 307,344; p. 206 Hawthorn, pis. 719, 720; p. 165 Heath family, p. 188 Hedeoma, pis. 241,366; p. 195 Helenium, pis. 290, 291,350; p. 204 Helianthus, pis. 276-278,401, 503; p. 203 Heliotrope, pi. 661; p. 193 Heliotropium, pi. 661; fig. 259; p. 193 Hemizonia, pis. 286, 287,415; p. 204 Hemlock, pi. 680; p. 126 Henbit, pis. 245,510; p. 196 Heterotheca, Heterotheca, pis. 265, 345; p. 202 Hibiscus, Hibiscus, pis. 654, 655; fig. 208; p. 182 Hieracium, pis. 307,344; p. 206 Hippuris, pi. 556; fig. 222; p. 186 Hoarypea, pis. 140,467; p. 170 Hogpeanut, pi. 815; p. 173 Holcus, pi. 15; p. 133 n. 3 Holly, pi. 749; p. 178 Holly family, p. 178 Honeysuckle, pis. 799, 800; p. 200 Honeysuckle family, p. 200 Hop-hornbeam, pi. 688; p. 143 Hordeum, pis. 11, 513; p. 133 n. 3 Hornbeam, pi. 687; p. 143 Hornpondweed, pi. 541; p. 131 Horsenettle, pi. 247 Huckleberry, pi. 780; p. 189 Hydrocharitaceae, p. 132 Hydrocotyle.pl 660; fig. 227; p. 187 Hypericaceae, p. 182

215

INDEX

Hypericum, pi. 817; p. 183 Hypoxis, pi. 808; fig. 53; p. 141

Lespedeza, Lespedeza, pis. 148-152, 473; figs. 164-166; p. 171 Lettuce. See Wild-lettuce Ilex, pis. 745-749; fig. 190; p. 178 Liatris, pis. 261, 346; p. 201 Impatiens, pi. 816; fig. 194; p. 179 Ligustrum, pi. 790; fig. 247; p. 191 Indigo, pis. 139,472; p. 170 Liliaceae, p. 140 Indigofera, pis. 139,472; fig. 156; p. 170 Lily family, p. 140 Inkberry, pi. 747 Linaceae, p. 174 Ipomoea, pis. 217-219, 339, 410; fig. 252; Linaria, pis. 253, 254,319, 427; fig. 269; p. p. 192 197 Iridaceae, p. 142 Lindera, pi. 708; p. 160 Iris family, p. 142 Linum, pis. 164,491, 526; fig. 170; p. 174 Ironweed, pi. 665; p. 201 Liquidambar, pi. 709; fig. 127; p. 164 Iva, pis. 668, 669; p. 202 Liriodendron, pi. 704; fig. 118; p. 160 Lithospermum, pis. 228, 229, 378; p. 193 Jacquemontia, Jacquemontia, pis. 216, Loasa family; p. 183 Loasaceae, p. 183 412; fig. 253; p. 192 Loco, pis. 141, 142,484; p. 171 Jerseytea, pi. 761; p. 180 Locust, Black, pi. 737; p. 170 Jessamine, pi. 791; p. 191 Logania family, p. 191 Jewelweed, pi. 816; p. 179 Loganiaceae, p. 191 Johnny-jump-up, pis. 195, 375 Lolium, pis. 13, 14; p. 133 n. 3 Johnsongrass, pi. 44; p. 133 n. 3 Lonicera, pis. 799, 800; fig. 285; p. 200 Jointvetch, pis. 144,481; p. 171 Loosestrife family, p. 185 Juncaceae, p. 140 Lotus (Deervetch), pis. 131-135, 353, 398, Juncus, pis. 628,629; fig. 48; p. 140 468; fig. 153; p. 169 Juniper, pi. 683; p. 126 Lotus (Nelumbo), pi. 553; p. 158 Juniperus, pis. 682, 683; fig. 9; p. 126 Lupine, pis. 121-124, 465,466; p. 169 Jussiaea, pis. 657, 658; p. 186 Lupinus, pis. 121-124,465, 466; p. 169 Lychnis, pis. 83,445; fig. 101; p. 156 Kallstroemia, pis. 171, 496; p. 175 Lycopus, pi. 662; p. 196 Knotgrass, pi. 570; p. 133 n. 3 Knotweed, pis. 53, 54, 418, 420, 635, 636; Lythraceae, p. 185 fig. 76; p. 147 Maclura, pi. 701; fig. 65; p. 146 Kochia, pis. 63,331, 509; fig. 84; p. 152 Madder family, p. 199 Labiatae, p. 195 Madia, pis. 284, 285,406; p. 203 Madrone, pi. 779; p. 189 Lactuca, pis. 305, 306, 404; p. 206 Magnolia, Magnolia, pis. 705, 706; fig. Lambsquarters, pi. 57 117; p. 160 Lamium, pis. 245, 510; fig. 264; p. 196 Magnolia family, p. 160 Larkspur, pis. 85, 86,335,430; p. 159 Magnoliaceae, p. 160 Larrea, pi. 738; fig. 174; p. 175 Maianthemum, pi. 807; fig. 51; p. 140 Lathyrus, pis. 155, 156,356; p. 172 Mallow family, p. 181 Lauraceae, p. 160 Malus, pi. 712; fig. 129; p. 164 Laurel family, p. 160 Malvaceae, p. 181 Leadplant, pi. 736; p. 170 Malvastrum, pis. 193, 489; fig. 206; p. 181 Leersia, pi. 567; p. 133 n. 3 Mammillaria, pis. 205, 487; figs. 216, 217; Leguminosae, p. 167 p. 184 Lepidium, pis. 96, 97, 314, 369, 508; p. 162 Mannagrass, pis. 560, 561; p. 133 n. 3 Leptochloa, pi. 562; p. 133 n. 3 Manzanita, pi. 778; p. 189 Leptoloma, Leptoloma, pi. 30; p. 133 n. 3

216

INDEX

Maple, pis. 752-755; p. 178 Maple family, p. 178 Marestail, pi. 556; p. 186 Marshelder, p. 202 Mayweed, pis. 292,374; p. 204 Medicago, pis. 125, 480, 522; fig. 151; p. 169 Melilotus, pis. 136, 137, 479; fig. 154; p. 169 Melochia, fig. 209; p. 182 Melon family, p. 201 Menispermaceae, p. 159 Menispermum, pi. 813; fig. 116; p. 160 Mentha, pi. 663; p. 196 Mentzelia, pis. 200, 201, 321, 385; figs. 212, 213; p. 183 Mermaidweed, pi. 559; p. 187 Mesquite, pi. 733; p. 167 Milkpea, pis. 162,474; p. 173 Milk Thistle, pis. 300, 393; p. 205 Milkweed, pis. 212, 320; p. 191 Milkweed family, p. 191 Milkwort, pis. 172, 173,341; p. 175 Milkwort family, p. 175 Mimosa, Mimosa, pi. 735; fig. 144; p. 168 Minerslettuce, pis. 74,438; p. 155 Mint, pi. 663; p. 196 Mint family, p. 195 Mitchella, pi. 820; fig. 278; p. 199 Moleweed, pi. 190 Mollugo, pis. 72,448; fig. 91; p. 154 Monarda, pis. 242, 497; p. 195 Montia, pis. 74,438; fig. 94; p. 155 Moonseed, pi. 813; p. 160 Moonseed family, p. 159 Moraceae, p. 145 Morning-glory, pis. 214, 215, 217-219, 339, 410,411; p. 192 Morning-glory family, p. 191 Morns, pis. 702, 703, fig. 64; p. 145 Mountain-ash, pi. 716; p. 165 Muhlenbergia, pi. 17; p. 133 n. 3 Mulberry, pis. 702, 703; p. 145 Mulberry family, p. 145 Mullein, pis. 252, 425; p. 197 Muscadine, pi. 764 Mustard, pis. 100,364; p. 163 Mustard family, p. 162 Myosotis, pis. 230, 440; p. 194 Myrica, pi. 686; fig. 55; p. 142

Myricaceae, p. 142 Myriophyllum, pis. 557, 558; fig. 223; p. 187 Naiad, pis. 544-546; p. 131 Najadaceae, p. 127 Najas, pis. 544-546; p. 131 Needlegrass, pi. 18; p. 133 n. 3 Needlerush, pi. 629 Nelumbo, pi. 553; fig. 107; p. 158 Nettle, pi. 809; p. 146 Nettle family, p. 146 Nightshade, pis. 246, 248, 456; p. 196 Nightshade family, p. 196 Nimblewill, pi. 17; p. 133 n. 3 Noseburn, pis. 183, 352; p. 176 Nuphar, pi. 550; fig. 105; p. 157 Nyctaginaceae, p. 153 Nymphaea, pis. 551, 552; fig. 106; p. 157 Nymphaeaceae, p. 157 Nyssa, pi. 769; fig. 232; p. 188 Oak, pis. 692-696; fig. 61; p. 144 Oats, pi. 514; p. 133 n. 3 Oats, Wild, pi. 12; p. 133 n. 3 Oenothera, pis. 207-209, 313, 332, 429; p. 186

Oleaceae, p. 190 Olive family, p. 190 Onagraceae, p. 185 Opuntia, pis. 202, 203, 455; figs. 214, 215; p. 184 Oregongrape, pis. 89,407 Oryza, pi. 517; p. 133 n. 3 Osage-orange, pi. 701; p. 146 Ostrya, pi. 688; fig. 56; p. 143 Oxalidaceae, p. 174 Oxalis, Oxalis, pis. 165, 451; fig. 171; p. 174 Oxalis family, p. 174 Oxeye Daisy, pis. 294, 387; p. 204 Oxybaphus, pis. 70,377; fig. 89; p. 153 Paintbrush, pis. 256, 376; p. 198 Panicum, Panicum, pis. 34-37, 310, 520, 571-574; fig. 24; p. 133 n. 3 Papaver, pis. 92,363; figs. 122,123; p. 161 Papaveraceae, p. 161 Parietaria, pi. 811; fig. 68; p. 146 Parsley family, p. 187

217

INDEX

Parthenocissus, pi. 766; fig. 203; p. 181 Partridgeberry, pi. 820; p. 199 Partridgepea, pis. 117, 118,464; p. 168 Paspalum, Paspalum, pis. 31-33,309, 570; fig. 24; p. 133 n. 3 Passiflora, pis. 198, 199, 450; fig. 211; p. 183 Passifioraceae, p. 183 Passionflower, pis. 198, 199,450; p. 183 Passionflower family, p. 183 Pear, pi. 713; p. 164 Peavine, pis. 155, 156,356; p. 172 Pedalia family, p. 198 Pedaliaceae, p. 198 Pellitory, pi. 811; p. 146 Pennyroyal, False, pis. 241,366; p. 195 Pennywort, pi. 660; p. 187 Penstemon, Penstemon, pis. 255,431; figs. 270, 271; p. 197 Peppervine, pi. 765; p. 181 Pepperweed, pis. 96, 97, 314, 369, 508; p. 162

Persimmon, pi. 786; p. 190 Phalaris, pis. 516, 566; p. 133 n. 3 Phaseolus, pis. 163,482, 525; p. 173 Phleum, pi. 515; p. 133 n. 3 Phlox, Phlox, pis. 224, 501; fig. 258; p. 193 Phlox family, p. 192 Photinia, pi. 714; fig. 130; p. 165 Physalis, pis. 250, 251,457; fig. 267; p. 196 Phytolacca, pis. 71,437; fig. 90; p. 154 Phytolaccaceae, p. 154 Picea, pi. 677; fig. 5; p. 125 Pickerelweed, pi. 627; p. 140 Pickerelweed family, p. 139 Pigweed, pis. 65-67,436; p. 153 Pigweed family, p. 153 Pinaceae, p. 125 Pine, pis. 672-676; figs. 2, 3; p. 125 Pine family, p. 125 Pink family, p. 155 Pinus, pis. 672-676; figs. 2-4; p. 125 Plagiobothrys, pis. 232, 233,506; p. 194 Plantaginaceae, p. 199 Plantago, pis. 257-259, 428, 502; fig. 276; p. 199 Plantain, pis. 257, 259,428; p. 199 Plantain family, p. 199 Platanaceae, p. 164 Platanus, pi. 711; fig. 128; p. 164

218

Plum, pi. 730; p. 166 Poa, pis. 7, 8; p. 133 n. 3 Poison-ivy, pi. 740; p. 178 Pokeberry, pis. 71,437; p. 154 Pokeberry family, p. 154 Polanisia, pis. 93,452; fig. 124; p. 162 Polemoniaceae, p. 192 Polygala, pis. 172, 113,341; figs. 175, 176; p. 175 Polygalaceae, p. 175 Polygonaceae, p. 147 Polygonatum, pi. 806; fig. 50; p. 140 Polygonum, pis. 53-55,418,420,421, 631642; figs. 71-76; p. 147 Pondweed, pis. 529-539; figs. 13-16; p. 127 Pondweed family, p. 127 Pontederia, pi. 627; fig. 47; p. 140 Pontederiaceae, p. 139 Popcornflower, pis. 232, 233,506; p. 194 Poppy, pis. 92,363; p. 161 Poppy family, p. 161 Portulaca, pis. 75, 76,447; fig. 95; p. 155 Portulacaceae, p. 154 Possumhaw, pi. 748 Potamogeton, pis. 529-539; figs. 13-16; p. 127 Potentilla, pis. 108, 109, 485; fig. 140; p. 166 Prairie-coneflower, pis. 275, 337; p. 203 Prairiestar, pis. 200, 201,321, 385; p. 183 Pricklypear, pis. 202, 203,455; p. 184 Pricklypoppy, pis. 90,359; p. 161 Privet, pi. 790; p. 191 Proserpinaca, pi. 559; fig. 224; p. 187 Proso, pi. 520; p. 133 n. 3 Prosopis, pis. 733, 734; fig. 141; p. 167 Prunella, pis. 240, 505; p. 196 Prunus, pis. 726-730; fig. 138; p. 166 Pseudotsuga, pi. 681; fig. 8; p. 126 Psoralea, pis. 138,471; p. 169 Puncturevine, pis. 170,328; p. 175 Purpletop, pi. 6; p. 133 n. 3 Purslane, pis. 75, 76,447; p. 155 Purslane family, p. 154 Pyrus, pi. 713; p. 164 Quackgrass, pi. 10; p. 133 n. 3 Queen-Annes-lace, p. 188 Queensdelight, pis. 184,460, 653; p. 176

INDEX

Quercus, pis. 692-696; fig. 61; p. 144 Ragweed, pis. 269-272, 329, 433; p. 203 Ranunculaceae, p. 158 Ranunculus, pis. 647-652; figs. 109-111; p. 158 Raspberry, pi. 723; p. 166 Ratibida, pis. 275,337; p. 203 Redcedar, pi. 682; p. 126 Redmaids, pis. 73,439; p. 154 Redtop, pi. 16; p. 133 n. 3 Rescuegrass, pi. 2; p. 133 n. 3 Rhamnaceae, p. 179 Rhamnus, pis. 756, 757; figs. 195-197; p. 179 Rhus, pis. 741-744; figs. 187, 188; p. 177 Rhynchosia, Rhynchosia, pis. 158, 470; p. 173 Rhynchospora, pis. 597, 598; fig. 33; p. 137 Rice, pi. 517; p. 133 n. 3 Rice Cutgrass, pi. 567; p. 133 n. 3 Ringwing, pis. 59, 315, 454; p. 151 Robinia, pi. 737; fig. 158; p. 170 Rockcress, pis. 105, 106, 324; p. 163 Rosa, pis. 724, 725; fig. 136; p. 166 Rosaceae, p. 164 Rose, pis. 724, 725; p. 166 Rose family, p. 164 Rosemallow, pis. 654, 655; p. 182 Rosinweed, p. 202 Rubiaceae, p. 199 Rubus, pis. 721-723; fig. 137; p. 166 Rudbeckia, pis. 273, 274,396; p. 203 Rumex, pis. 51, 52,417, 422; fig. 70; p. 147 Ruppia, pi. 540; fig. 17; p. 131 Rush, pis. 628, 629; p. 140 Rush family, p. 140 Russianolive, pi. 767; p. 185 Russianthistle, pis. 64, 316, 380; p. 152 Rye, pi. 512; p. 133 n. 3 Ryegrass, pis. 13, 14; p. 133 n. 3 Sage, pis. 243, 244, 442; p. 196 Sagittaria, pis. 623-625;figs.20,21 ; p. 132 St. Andrewscross, pi. 818; p. 183 St. Johnswort, pi. 817; p. 183 St. Johnswort family, p. 182 Salmonberry, pi. 722 Salsola, pis. 64, 316, 380; p. 152 Saltbush, pis. 60,61,572, 435; p. 152

Saltgrass, pis. 563, 564; p. 133 n. 3 Salvia, pis. 243, 244,442; p. 196 Sambucus, pi. 796; fig. 283; p. 200 Sandbur, pi. 41; p. 133 n. 3 Sandverbena, pis. 69,383; p. 153 Sapodilla family, p. 190 Saponaria, pi. 84; figs. 102, 103; p. 156 Sapotaceae, p. 190 Sassafras, Sassafras, pi. 707; fig. 119; p. 160 Sawgrass, pi. 615; p. 138 Schrankia, pis. 116,372; fig. 142; p. 167 Scirpus, pis. 599-612; figs. 34-38; p. 137 Scieria, Scleria, pis. 613, 614; figs. 39, 40; p. 137 Screwbean, pi. 734; p. 167 Scrophulariaceae, p. 197 Scurfpea, pis. 138,471; p. 169 Scutellaria, pis. 239, 334, 360; p. 195 Seablite, pi. 643; p. 152 Sea-purslane, pi. 646; p. 154 Secale, pi. 512; p. 133 n. 3 Sedge, pis. 616-619; p. 138 Sedge family, p. 135 Selfheal, pis. 240, 505; p. 196 Senna, pis. 114, 115,461, 463; p. 168 Sensitivebrier, pis. 116,372; p. 167 Serinea, Serinea, pis. 302, 386; p. 205 Serviceberry, pi. 717; p. 165 Sesame, pi. 527; p. 198 Sesamum, pi. 527; fig. 275; p. 198 Sesbania, pis. 143,390; fig. 159; p. 170 Sesuvium, pi. 646; fig. 92; p. 154 Setaria, pis. 38-40; fig. 24; p. 133 n. 3 Sheep Sorrel, pis. 51, ¥77 Shepherdia, pi. 768; fig. 221; p. 185 Shepherds-purse, pis. 98,498; p. 162 Sida, Sida, pis. 194,409; fig. 207; p. 182 Sidalcea, pis. 192, 490; fig. 205; p. 181 Silene, pis. 81, 82,444; fig. 100; p. 156 Silybum, pis. 300, 393; p. 205 Sisymbrium, pis. 99,499; p. 163 Sisyrinchium, pi. 630; fig. 54; p. 142 Skullcap, pis. 239, 334, 360; p. 195 Skunkbush, pi. 744 Smartweed, pis. 631-633, 637-641; figs. 74, 75; p. 147 Smilacina, pi. 805; fig. 49; p. 140 Smilax, pis. 684, 685; fig. 52; p. 141 Snailseed, pi. 812; p. 159

219

INDEX

Snakeweed, pis. 264, 388; p. 202 Strophostyles, pis. 159-161, 371, 394; fig. Sneezeweed, pi. 291; p. 204 169; p. 173 Snowberry, pi. 798; p. 200 Suaeda, pi. 643; fig. 85; p. 152 Soapwort, p. 156 Sudangrass, pi. 518; p. 133 n. 3 Soja (synonym of Glycine), p. 172 Sumac, pis. 741-743; p. 177 Solanaceae, p. 196 Summer-cypress, pis. 63, 331, 509; p. 152 Solanum, pis. 246-249,456, 492; figs. 265, Sumpweed, pis. 668, 669; p. 202 Sundrops, pis. 209, 332 266; p. 196 Sunflower, pis. 276-278,401, 503; p. 203 Solidago, pis. 266, 267, 347; p. 202 Supplejack, pi. 758; p. 180 Solomonseal, pi. 806; p. 140 Sweetclover, pis. 136, 137,479; p. 169 Solomonseal, False, pi. 805; p. 140 * Sweetgum, pi. 709; p. 164 Sonchus, pi. 304; p. 205 Switchgrass, pi. 573; p. 133 n. 3 Sorbus, pi. 716; fig. 132; p. 165 Sorghum, Sorghum, pis. 44, 518, 519; p. Sycamore, pi. 711; p. 164 Sycamore family, p. 164 133 n. 3 Symphoricarpos, pis. 797, 798; fig. 284; p. Sorrel, Sheep, pis. 51,417 Sowthistle, pi. 304; p. 205 200 Soybean, pi. 523; p. 172 Sparganiaceae, p. 127 Tansymustard, pi. 104; p. 163 Sparganium, pis. 621, 622; figs. 11, 12; p. Taraxacum, pis. 303,399; p. 205 Tarweed, pis. 284-287, 406, 415; pp. 203, 127 Spartina, pi. 565; p. 133 n. 3 204 Spatterdock, pi. 550; p. 157 Tearthumb, pis. 634, 642 Specularia, fig. 287; p. 201 Tecoma, pi. 793; p. 198 Speedwell, pi. 819; p. 198 Tephrosia, pis. 140,467; fig. 157; p. 170 Spergula, pis. 77,354, 458; fig. 96; p. 155 Teucrium, pis. 237,361; fig. 262; p. 195 Sphaeralcea, pis. 191,488; fig. 204; p. 181 Thimbleberry, pi. 721 Spicebush, pi. 708; p. 160 Thistle, pis. 295, 296,392; p. 205 Spiderflower, pis. 94, 95,453; p. 162 Thistle, Milk, pis. 300,393; p. 205 Spiderling, pis. 68,423; p. 153 Three-awn, pi. 21; p. 133 n. 3 Spiderwort, pis. 48,495; p. 139 •Tickclover, pis. 145-147,478; p. 171 Spikenard, pi. 771 Tickseed, pis. 62,318; p. 152 Spikerush, pis. 584-594; p. 136 Timothy, pi. 515; p. 133 n. 3 Sporobolus, pis. 19, 20, 507; fig. 24; p. 133 Toadflax, pis. 253,427; p. 197 n. 3 Toxicodendron, pi. 740; fig. 189; p. 178 Toyon, pi. 714; p. 165 Sprangletop, pi. 562; p. 133 n. 3 Spruce, pi. 677; p. 125 Tradescantia, pis. 48, 495; fig. 46; p. 139 Spurge, pis. 185-189, 367, 426,449; p. 177 Tragia, pis. 183,352; fig. 181; p. 176 Trapa, pi. 555; p. 186 Spurge family, p. 175 Spurry, pis. 77, 354, 458; p. 155 Trapaceae, p. 186 Stargrass, Yellow, pi. 808; p. 141 Tribulus, pis. 170, 328; p. 175 Starthistle, pi. 297; p. 205 Trichostema, pis. 238, 333; fig. 263; p. 195 Stellaria, pis. 78,443; fig. 97; p. 155 Tridens, pi. 6; p. 133 n. 3 Trifolium, pis. 126-130, 477; fig. 152; p. Sterculiaceafe, p. 182 Sticktight, pis. 670, 671; p. 204 169 Stillingia, pis. 184, 460, 653; fig. 182; p. Triticum, pi. 511; p. 133 n. 3 Trumpetvine, pi. 793; p. 198 176 Tsuga, pi. 680; fig. 7; p. 126 Stinkgrass, pis. 9,365; p. 133 n. 3 Tuliptree, pi. 704; p. 160 Stipa, pi. 18; p. 133 n. 3 Tumblemustard, pis. 99,499; p. 163 Strawberry, pis. 107,486; p. 166

220

INDEX

Turkeymullein, pis. 179,408; p. 176 Typha, pi. 620; fig. 10; p. 126 Typhaceae, p. 126 Ulmaceae, p. 145 Ulmus, pis. 697, 698; fig. 62; p. 145 Umbelliferae, p. 187 Umbrellawort, pis. 70,377; p. 153 Unióla, Unióla, pi. 804; p. 133 n. 3 Urtica, pi. 809; fig. 66; p. 146 Urticaceae, p. 146 Vaccinium, pis. 782-784; figs. 239, 240; p. 189 Vallisneria, pi. 547; fig. 23; p. 132 Velvetgrass, pi. 15; p. 133 n. 3 Venus Looking-glass, p. 201 Verbascum, pis. 252,425; fig. 268; p. 197 Verbena, Verbena, pis. 234-236, 397; fig. 260; p. 194 Verbena family, p. 194 Verbenaceae, p. 194 Verbesina, pis. 281-283,323, 327; p. 203 Vernonia, pi. 665; p. 201 Veronica, pi. 819; fig. 273; p. 198 Vetch, pis. 153, 154, 355; p. 172 Viburnum, Viburnum, pis. 801-803; fig. 286; p. 200 Vicia, pis. 153, 154,355; p. 172 Vigna, pi. 524; p. 172 Viola, pis. 195-197, 375; fig. 210; p. 183 Violaceae, p. 183 Violet, pis. 195-197,375; p. 183 Violet family, p. 183 Vitaceae, p. 180 Vitis, pis. 762-764; fig. 201; p. 181 Wahoo, pi. 751; p. 178 Wartgrass, pi. 572; p. 133 n. 3 Watercaltrop, p. 186 Waterchestnut, pi. 555; p. 186 Waterchestnut family, p. 186

Waterhemp, pis. 644, 645; p. 153 Waterhyacinth, pi. 548; p. 139 Waterhyssop, pi. 664; p. 198 Waterlily, pis. 551, 552; p. 157 Waterlily family, p. 157 Watermelon, pi. 528; p. 201 Watermilfoil, pis. 557, 558; p. 187 Watermilfoil family, p. 186 Waterplantain family, p. 132 Waterprimrose, pis. 657,658; p. 186 Waterprivet, pi. 787; p. 191 Watershield, pi. 554; p. 158 Waterweed, pi. 543; p. 132 Waterwillow, pi. 656; p. 185 Waxmyrtle, p. 142 Waxmyrtle family, p. 142 Wheat, pi. 511; p. 133 n. 3 Widgeongrass, pi. 540; p. 131 Wildbean, pis. 159-161,371, 394; p. 173 Wildcarrot, pis. 211, 336; p. 188 Wildcelery, pi. 547; p. 132 Wild-lettuce, pis. 305, 306, 404; p. 206 Wildmillet, pis. 575-577; p. 133 n. 3 Wild Oats, pi. 12; p. 133 n. 3 Wildrice, pi. 568; p. 133 n. 3 Winterberry, pis. 745, 746 Wintercress, pis. 102, 103, 469; p. 163 Wintergreen, pi. 776; p. 189 Witchgrass, pi. 34; p. 133 n. 3 Witch-hazel, pi. 710; p. 163 Witch-hazel family, p. 163 Woodbine, pi. 766; p. 181 Wormseed, pi. 56 Yarrow, pi. 293; p. 204 Yellow Stargrass, pi. 808; p. 141 Zannichellia, pi. 541; fig. 18; p. 131 Zizania, pi. 568; fig. 24; p. 133 n. 3 Zizaniopsis, pi. 569; fig. 24; p. 133 n. 3 Zostera, pi. 542; fig. 19; p. 131 Zygophyllaceae, p. 175

221